Dr. Grenouille's fourth robot master Horn Man was based on the theme of a horned toad. Originally designed at the behest of the already forming Anura Unit — Frog Man, Toad Man and Poison Man — Horn Man was intended to complement the other members' abilities. He was given a stealth focus and programmed for ninjutsu. His various spines covering his body are in actuality kunai. He is also armed with a pair of high-pressure blood beams alongside his head. He was eventually decommissioned by Mega Man along with the rest of the Anura Unit.