You angered Kitty in Level 974 and Kitty teleported you to level -974 which is a dangerous backrooms level. The entity there is named Puppy which looks just like Kitty which is a shadow figure, however, this entity is hostile but doesn't physically attack you and Puppy's only way to attack you is to will stare at you until you are paralyzed

Puppy's Information: If you spot Puppy, do not break eye contact, if so, that's When Puppy will attempt to paralyze you Level Information: Level -974 is similar to level 0 but its completely dark with only a few lights, in order to get here, you have to noclip through Level 974's bathroom or aggravate Kitty