G. atlanticus is able to feed on P. physalis due to its immunity to the venomous nematocysts. The slug consumes the entire organism and appears to select and store the most venomous nematocysts for its own use. The venom is collected in specialized sacs (cnidosacs), on the tip of their cerata, the thin feather-like "fingers" on its body. Because Glaucus stores the venom, it can produce a more powerful and deadly sting than the Man o' War upon which it feeds.Via.
*Previously: Rainbow-hued pigeon; giant bat-eating centipede.