I found that CHAIN in Roblox is described as a monster/entity , not a “form” in the usual avatar sense. The wiki says CHAIN is the main antagonist and a lumberjack-like killer with a cursed mask and chainsaw.

What that means

  • If you mean the character type , CHAIN is a monster / antagonist.
  • If you mean a game mode form , the available info I found points to Survival as the gamemode where CHAIN hunts players.
  • If you meant the Roblox item named “Chain” , that is just a neck accessory for avatars, not a form.

Quick read

So the best answer is: CHAIN’s form type is monster/entity, specifically a killer antagonist.