Down in the Sewer area near the train track entrance; it is sitting on your left as soon as you walk down the stairs.

If you are hunting for the post-game secret bunnies in Animal Well:

Players highly utilize the Electrical Condense transcendent module for high-tier dungeon farming.

If you are looking for endgame guides for the character (who is listed as playable character No. 06 in some roster lists):

This specific bunny is infamous among players because it does not have a set, static spawn point on the grid like most others.