Chomp

Chomp is a monster that hatches out of an egg at the start of the game and follows you around and can evolve into different forms. Chomp starts out in his foundling form. And the evolution trees that Chomp has is child, teen, and adult.

Chomp is your game companion who can evolve into many different forms. He is first found after a bit of tutorial with Ellie, in a steam punk-ish room after hatching from an egg. You will first see his egg, and no further reaction will occur until you try to leave the room. The egg will then shudder, and a foundling will hatch out of the egg, unlocking the Pet Sanctuary and initiating a cutscene. You will then be allowed to leave the room, but chomp will follow. After noticing he is hungry, Ellie settles on the name Chomp. Your adventure will then start.