Enemy 1: Mimic & Mega-Mimic (Slimes)
Only recently discovered due to it's abilities. This strange slime can copy almost anything it comes across.

Appearance:
A white, almost translucent Jelly cube with a purple core. The surface of it bubbles as if it were boiling/unstable. The Mega-Mimic is the same, only larger.

Ability:
Upon spawning the Mimic goes towards the nearest (preferably non-slime) enemy and 'pokes' it, whereupon it turns into a copy of that enemy. These copies behave exactly like the original monster, but have the Mimics white-and-purple colour scheme and have Slime damages and resistances (i.e. if a Mimic copies a Zombie, it behaves like a Zombie, but does Piercing and is weak to Shadow) along with the Mimic's status (if the Mimic had one). Mimics are also capable of un-transforming if they want (say because they've seen something stronger to copy)

Tier 3 Mimics can also copy Knights if they get close enough to 'poke' them. Mimic Knights have access to every weapon the original does and behave like Mecha Knights, Devilites or Gremlin Demos depending on whether their current weapon is a Sword, Gun or Bomb respectively.

The Mega Mimic works the same way, but the copied target is twice the size, has twice as much health & damage, but only half the move & attack speed. They cannot un-transform and once they have chosen to mimic something they are stuck with what they chose.

Variants:
Status Mimics are slightly different colours (i.e. the Fire Mimic has pale red where a normal one has white)

Shock: Mirror Mimic
Fire: Mirage Mimic
Poison: Hallucinatory Mimic
Frost: Reflected Mimic
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Enemy 2: Custodian (Undead)
Believed to be some form of undead Owlite, these mysterious phantoms can usually be found in the more empty parts of the Clockworks, seemingly looking for something/someone...

Appearance:
A large hooded figure in black robes that carries a Tome in one hand and a large staff with 3 bells tied to it in the other. Tier 2 versions have a gold trim on their robes and the Tier 3 ones also have runes woven into them. It does not have any legs and simply floats above the ground.

Notes:
The Custodian is completely blind and reacts to noises (Enemies/Knights being hit, Guns being fired, thrown objects hitting the wall, Bombs going off etc.) rather than sight. Has a LOT of health, but seldom has to actually be killed to progress.

Attack 1:
The Custodian points his staff forwards and sends out a large AoE bullet that flies to the targeted location and then explodes. This also spits out 4 and 8 bullets at Tiers 2 & 3 respectively.

Attack 2 (Tier 2 & 3):
The Custodian drives his staff into the ground, generating a powerful shockwave. The Custodian usually only uses this ability if he himself is being attacked.

Ability 1 (Tier 2 & 3):
The Custodian shakes his staff from side to side, creating several 'Echoes' that travel outward, any Knight caught in an Echo can be 'seen' by the Custodian for 5-10 seconds for Tier 2 and 3 respectively)

Ability 2 (Tier 3):
Summons three "Phantom bells". These bells move and attack very quickly, but do no damage (their attack is solely to 'mark' the target for the Custodian) and have little health. They have no resistances or weaknesses.

Variants:
Status Custodian wear robes coloured around their Status (Dark red for Fire, Dark green for Poison etc.)

Shock: Weather Wizard
Fire: Pyromancer Custodian
Poison: Biologist Custodian
Frost: Cyromancer Custodian
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Enemy 3: Blade Jelly (Slime)
These mighty slimes appear to be some sort of protector that the various Dukes and Royals of Slime have started using as bodyguards. Rumor has it their inspiration for this has come from seeing the effectiveness of the Spiral Knights in action.

Appearance:
A spiky, metallic slime with a shape that resembles a hybrid of Jelly Cube and Lichen. Larger than most other Slimes.

Ability:
The Blade Jelly takes much less damage due to its protective shell, which it only lowers when attacking.

Attack 1:
The Blade Jelly creates a tendril, which it then tries to use to harpoon the target. After 'firing' it takes a few seconds to reel it back in, during which it is vulnerable (higher Tiers reel in faster) This attack is slow, but has good range and damage.

Attack 2 (Tier 2 & 3):
Spikes burst out of the Blade Jelly, damaging everyone nearby. It is vulnerable for a split-second or two after performing this move

Attack 3 (Tier 3):
The Blade Jelly grows several blades outwards in a (counter-?)clockwise formation, giving it the appearance of a Buzzsaw. It then spins around madly similar to Royal Jelly. It is invincible while doing this but can be 'redirected' through use of knockback/shield-bashing, even being used to hurt other enemies.

Variants:
Shock: Charged Blade Jelly (Has a Quicksilver-like texture, emits sparks)
Fire: Molten Blade Jelly (Glows red hot)
Poison: Tetanus Blade Jelly (Rusty appearance)
Frost: Cold Iron Blade Jelly (Much darker colours, seems to glow from within)