's Lair first appears in Mortal Kombat 4. It returns in Mortal Kombat Deception in a more dynamic form.
Mortal Kombat 4Reptile
keeps a tidy house. The stage is typical to most in this installment of Mortal Kombat, no interaction with the environment save for the occasional throwing object (boulders in this case). Green steam, from the roiling acid baths, slowly animates in the background, along with the silhouettes of chained prisoners, presumably awaiting some grisly end.
Mortal Kombat Deception Reptile's Lair has seen some major changes. The fight now opens on a platform set over a larger fighting circle. One opponent may knock the other down into the lower level by striking the first player when they are positioned on the edge of the top platform. The unfortunate combatant falls downward and strikes a poison egg, which breaks open spewing poison vapor. The lower stage level is ringed with these poison eggs. Each time a player is pressed to the edge of the platform, they can be knocked into an egg which then spews more poison gas, eating away at the player's healthbar.
There is no stage deathtrap.