Venus Mantrap

Human Bird Grass was a Mysterious Being that attacks a sponsor of the Hero Association with Junior Centipede.

Hero Hunt Arc
Human Bird Grass emerges from the ground with Junior Centipede at a restaurant. Junior Centipede briefly mentions that he is looking for the sponsor of Hero Association. Before they could grab the sponsor, Metal Bat grabs a coat and engages in a fight with him and his partner.

Centipede Arc
Human Bird Grass's corpse is being sat upon by Metal Bat.