Crystal Lumber

TL:DR to the bottom.
This is a Danger Mission. I told ya I would have posted this on my big suggestion thread that is now over the 10th page. probably. didn't check.
Strangers recently found out another ce cave, but when they got close, they were attacked by monsters apparently made of crystal. They asked Spiral HQ for help, and the recon knights have been tasked to investigate. the first rangers that got in there, though, were attacked by fiends! something is on in here...
New enemy: retrodes made of crystal. [name needed. crystalrodes? it's too long for me.] they have enchanted elemental defense, but they are still weak to it. They deal pure elemental damage and shock and stun. Yeah, both. They are also slightly bigger than normal, and they possibly track on the swipe. Please. I'm undecided if making them not-killable. once defeated, they stay down for a bit, then re-energize and keep fighting. for a while. that's why I'm undeciced. how to kill them?
First depth: Crystal Point
It’s an intricate, puzzle-like, normal clockworks level. You may find strange machinery (the ones that Strangers use to bring crystal from the cave to Heaven), and some blue, not glowing crystal on the way. It obviously has an obvious final arena. what it makes tricky is that the machinery of the strangers blocks your way like a wall, and the crystal like a low barrier. OOO has a lot of space to work with in here.
Waves are mainly composed by shock retrodes and greavers. normal, stun-dealing greavers. Last one is a crystal retrode with the support of a devilite group, pit bosses included.
NOTE: if crystal retrodes [name needed] are not killable, make one spawn at the beginning of the arena.
Second depth: The Crystal Cave
This is a deconstruction zone. You may find the machinery Stragers use to extract crystal energy. the level layout should be cave-like. Now, to the real uniqueness.
The center of the stage is blocked. With gates. There’s the elevator in there. Of course there is. To unlock it, there are four party buttons near some gates. You have to reach them, and to press them all. Once they are all pressed, the center is yours. Well, sort of…
Anyway, there are lots of crystal retrodes, lots of shock constructs and stun dealing monsters of the fiend family (greavers, trojans, devilite overtimers)
Once you get to the elevator, is still blocked. Party button. Crackling sound.
Boss: Crystal Lumber
Appearance: a two-armed lumber completely made of crystal.
Attacks:
2 arms smash the ground at the same time, causing a big explosion of energy.
2-combo attack: first an arm, then the other. On the second attack the crystal lumber jumps to lounge.
Summons crystal retrodes, if killable, every revive; if not killable, first and last.
When enough damage is dealt, he goes down but then arises again (similar to Arkus) and does an energy blast that stuns on impact and deals heavy knockback (less than a spark revive). This is done 3-4 times, then he is defeated.
from the first revive, he can pulse on the ground battlepod-like, dealing knockback and breaking freeze if it's frozen. (take that shivermist!) he also does a 180° spin, damaging with both arms, if the majority of damage is dealt from behind.
From second revive on, attacks from the crystal lumber make spikes of crystal emerge from the ground, and on the spin attack he lanuches lumps of crystals at you, dealing elemental damage (maybe like shard bombs, but undecided.)
I was thinking of a lazur attack, then I said nah.
When he is defeated, his body shatters many times. inspecting the body, you can find strange symbols on the crystals that have been his core; seems like devilites were afoot in his creation.
On the reward floor:
you can inspect a crystal that says that the crystal hasn’t got any more energy: the Lumber must have drained it all.
you find some rangers, and they seem interested in some crystals that bear devilite symbols. it's like they planned to trap some souls in the crystals, and the Crystal Lumber must have been their most succesful experiment. good thing you stopped them, imagine what they could do with this...
TL;DR: new danger mission with lots of strange machinery and crystal. new boss that (knowing OOO) will most probably will be semi-reskin of vanaduke.

The crystal retrode idea is decent. Nice to see a monster that actually seems somewhat difficult to handle. Retrodes already deal pure ele though, unless you are talking about the swipe. They should also only deal stun/shock on the laser, since it gives the effect of disorienting light flashes (Epilepsy anyone? o_0). Swipe deals only shock. You should also think about giving them a name, like Crystrode or soemthing.
~Crystal Point~
I suggest moving this area from the clockworks to some night time wilderness area, leading to the cave. This would make more sense, since you said the strangers found an actual crystal cave.
So are the machinery/dull crystals breakable? Or are they just straight up walls that you have to walk around to find your way out? You could use some more detail on the kind of puzzles that are going to appear here.
~Crystal Cave~
Again, I suggest this to be an actual cave. The layout of the floor can be exactly how you have it now, just make it cave themed instead of Decon Zone themed. This Decon zone type floor, is it similar to the first floor of GitM in that there are monsters walking around, gates to be opened and puzzles to be solved? or is it just like a regular Decon Zone? Or, is there nothing there at all and the only thing to do is press the party buttons? Does each party button spawn it's own set of monsters, or does nothing happen until all 4 are pressed?
~Crystal Lumber Boss~
This 2 arm smash, it sounds just like a Vanaduke mace smash copy, but with probably greater radius. Instead of a large explosion, make it instantly spawn random crystals from the ground that block the player's movement for a short time before breaking apart (possibly 2-4 seconds). When the crystals break, they deal damage to any surrounding players (probably either piercing or elemental, your choice).
I don't understand what you mean by " jumps to lounge". Unless you mean he lunges at you, like a dust bunny ,which wouldn't make sense since he is a huge lumber with limited mobility...
I also don't understand why you would have to kill it so many times before it stays down. Arkus did that because he used to be a spiral knight, and therefore had access to the energy revive system (before he becomes broke from all the revs, and subsequently dies permanently). Just make him have a single phase with massive health. Or, better yet, just have him shatter off pieces of his crystal body and grow slightly smaller each time he is defeated (2 shatters, thus 3 phases). He gets faster each time he shrinks, in relation to his reduced size. On the final phase, make crystals (damaging ones like I said before) automatically spawn randomly from the ground. This would force players to not just kite him to the back, since they would actually have to watch where they are going like against Vana and his shadow fires.
I hope that this boss actually moves around, and not just stands in one place like Maulos from HoI.
There is already a danger mission with a Construct/Undead combo. Maybe make the second monster type beast instead of undead. Yes, I know this would break the whole in danger missions, all main monsters families are weak to the same damage type trend, but it would at least avoid unoriginal monster pair-ups.

I'll edit the thingies I need when I finish posting.
you're right about crystal retrodes, although I'm not great at names. as for the swipe, I would like it dealt double status, cause then swordies wouldn't be advantaged. maybe adding an explosion. I'm undecided if making them not-killable. once defeated, they stay down for a bit, then re-energize and keep fighting. for a while. that's why I'm undeciced. how to kill them?
Crystal Point: I prefer retaining the tunnels layout. explanation: it's a passage just above/below the cave (still can't decide). it's not inside the cave, it's just a passageway.
machinery and crystals aren't breakable. I thought about breakable crystal, but I don't think OOO has the tools to make a breakable low barrier.
machinery will be a wall-like barrier and crystals a low barrier. I think I have already said that, but whatever.
Cave: all right, it will be a cave (probably punkin layout reskin). still deconstruction zone-like.
I think that there should be no arenas in the 4 initial party buttons. maybe more enemies spawn in the others.
as for the layout, I'm no level designer. you can do pretty things with the not-defined machinery and bunches of crystals of the size of a block. I'll let guys more experienced than me do the job for me.
Boss:
all right, I have to add things on this.
first, "jump to lounge" means it uses an arm as support and literally jumps and smashes the other.
as for the "spawn crystals" part, it spawn spikes form phase 2 on.
NEW attack: 180° spin when the majority of the damage comes from behind. strikes with both arms, so even the ones ahead of him should pay attention. on phase 3, lumps of crystal come out from his arms like bullets, causing obvious elemental damage. undecided if making these like shard bombs.
NEW attack: pulses on the ground battlepod-like, dealing knockback and breaking freeze if it's frozen. take that shivermist!
spikes from the ground are nefarious, since not everybody can see them coming. that's why I would like to make them kinda prevedible making them on attack only.
movement speed should be like a vana or slightly more.
for the revives, I want that lumber to suck up ALL the energy from those crystals. all of it.
how about fiends? mad experiment? it would give moar lore on the mission. seems like a good idea. EDIT: munor lore addidtion added.
arena changes, here they come!

Making the crystal retrodes un-killable would make them like phantoms: decent fighting capabilities and unable to kill them permanently. Since there is already a basis for this design, there is nothing wrong with adding it. However, you have to realize that it means they cannot drop money (unless you make it like zombies, where they only drop money on their first death). If you wanted to put an un-killable monster in an arena, just make it so that they are not the monster required to advance, similar to monsters from a re-spawning pad; they would possibly all shatter apart once the arena is finished.
Giving the retrodes stun on the swipe is acceptable I guess if an explosion animation is added. Just don't make it `100% chance of stun, as then players would complain about the difficulty (not me, but others).
For the 180˚spin, so he just turns around and attacks everyone behind him if you hit him too much from the back? That would be great, since it would make people stop running behind him for an easy kill.
Ok, your reasoning for the rev explosion seems legit. I also support the knock back on it, if it is a CE rev.
Fiend would be ok. But I would need to hear what you come up with for the lore to justify putting fiends in it.
bump.
added a TL;DR, for real on this thread.