I'm just jotting down a crazy idea I had while reading another thread.

Anyway... The Chimera is a horrific, gigantic Lichen colony of unclear origins. While its central core is a cluster that looks like any other slime, its outer shell is covered in uneven spines and growths that resemble monster body parts protruding out of it. Suspended in its inner layers is a collection of smaller cores that can be ejected from the main body onto the battle field (more on this later).

The levels leading to the boss is part of an abandoned waste processing plant. The entire area is covered with a toxic goo*, that poisons the Knights if they come into contact with it, and the area is infested with all manner of poisonous creatures from nearly every monster family. Players will also notice the monsters become progressively more "life less" the further down they go. This eventually take the players into the lowest level of the plant known as "The Purifier". At one point, the Purifier was used to remove contaminants from waste water created as a byproduct of various cooling systems and chemical processors throughout the clockworks. The plant had to be abandoned when the Chimera started attacking workers and destroying parts of the plant. Since then the whole place continued to collect toxic waste until it was over flowing with it.

The boss fight takes place in a storage tank below the Purifier's core systems. Scattered around the floor of the tank are small, slightly raised platforms, a drainage grate in the center, and each corner has an output pipe of the purifier located above it. The output pipes start the match obstructed by a green crystalline formation, and the floor is covered in green slime. Destroying the blockage allows clean water to flow into the tank and washes the slime away from that corner of the arena. If Knight stands under the pipe, its able to clear all status effects and slowly regain life.

During the fight, the Chimera's primary attack is to lash out at knights in melee range using a chunk of itself as club, and is able to hit a decent sized area in front of it. It targets and attacks based on 4 quadrants, with each quadrant able to attack independently. Periodically it'll also return to the middle of the arena. Once in the center, it'll agitate any part of the floor still covered in goo into a poisonous spike trap that lasts several seconds. When it clears, it'll leave behind random patches of toxic goo. During that time, it'll eject 4 cores from its inner layer into random spots of the arena. These cores will turn into doppelgangers** and take the shape of a random monster. The slime copies have the same attack and movement patterns as the monsters they copy with the exception of having no weakness or resistance aside from a moderate poison resistance. Killing a copy will leave behind a virulent slime core (more on this later). Just before it resumes moving again, it'll launch globs at the purifier pipes to restore the blockage and allow the slime to return on the floor.

The battle is novel in the fact that it allows 2 ways to defeat it. Players can either take the direct approach and just hammer away at it, but does come with certain risks of counter attack. The second method is a bit trickier, but less risky then directly attacking. Players can pick the virulent slime cores dropped by doppelgangers and put them down under the purifier pipe that has water running to transform it into a Purified slime core. This object can be picked up and thrown at the Chimera, causing its outer shell to harden in one quadrant. When the shell is hardened, that portion is unable to attack, but also unable to take damage. When all 4 quadrants are hardened, the chimera will wander around the map for a little while taking ticks of damage then move to the center of the arena. Once there it'll break off the harden shell and go through the usual spike trap/doppelganger routine.

*pulling this idea out since it would effectively kill the puzzle boss aspect* An alternative to the harden shell is to keep the inability to attack, but make the shell breakable from weapon damage and/or time limit, and have it deal DOT while in place. A coordinated team could effectively seal off the creature, prevent it from attacking, and continually damage it. There would need to be another counter attack available if this occurred as a way to tune risk assessment while trying to fight it. *idea pulled*

*Toxic goo is patch of floor hazard similar to shadowfire, but inflicts poison status instead of fire.
**Doppelganger is a new type of slime monster that takes a shape of a random basic monster shortly after it spawns. Aside from retaining its slime-like texture, its body shape and behavior is identical to the monster that it is copying. Its attacks all deal normal damage in place of the damage type normally associated with the monster, and it has no particular resistance or weakness to damage types. Because of this limitation, it doesn't make copies of monsters that have inherent status traits.

For those having trouble visualizing the mind blowing weirdness that this thing should look like.... this video is part of the inspiration for the monster concept. http://vimeo.com/7861415