Irukandji jellyfish eat non-insect arthropods and other marine invertebrates. Irukandji jellyfishes diet shifts from invertebrates to vertebrates as they mature. To paralyze their victims, box jellyfish use venom. This venom is released into the prey as soon as the prey triggers one of the jellyfishes stinging cells (nematocysts). When the stinging cell is activated, a harpoon-like coil is released, which stings the prey, and the jellyfish venom then flows through the prey via the harpoon. The tentacle will then retract back into the jellyfish, dragging the prey in.