Kleptocnidy is a term that describes the phenomenon by which predators consume cnidarian prey and sequester the cnidocytes from their meal (klepto = steal, cnidy = cnidocytes). One group of predators - the aeolid nudibranchs (like the one pictured, feeding on an upside down jelly) - deposit unfired cnidocytes in dorsal projections (called "cerata") to be used for their own defense. While these sea slugs may be the most famous practitioners of kleptocnidy, this phenomenon has evolved numerous times independently throughout the diversification of animals - even among ctenophores! (Check out this great review for the full story: Goodheart and Bely, 2017). Considering cnidocytes are packed with venom, it's not surprising that a predator would harvest these cellular weapons for their own protection - but, how do they do it? That's what our team is working to understand.