Many comb jellies also eat zooplankton but they use sticky cells (colloblasts), instead of stinging cells to collect their prey. Whereas sea jelly stinging cells are harpoon-like and deliver toxins, the sticky cells of the comb jellies act like glue and adhere to zooplankton. Since comb jellies don’t have toxins they are completely harmless to humans.
Some sea jellies eat other jellies. For example, the Lion’s Mane jelly (Cyanea) usually feeds on the Moon jelly (Aurelia aurita). Some lobate comb jellies have very wide mouths that allow them to engulf other comb jellies that are almost as large as themselves.