Portuguese man o' war
"G. atlanticus" is able to feed on the Portuguese man o' war due to its immunity to the venomous nematocysts. The slug consumes chunks of the organism and appears to select and store the most venomous nematocysts for its own use against future prey. The nematocysts are collected in specialized sacs (cnidosacs) at the tip of the animal's cerata, the thin feather-like "fingers" on its body. Because "Glaucus" concentrates the venom, it can produce a more powerful and deadly sting than the Man o' War on which it feeds.