Info
Interestingly, the symbiotic crab Zebrida adamsii White,1847 cohabits with the sea urchin and is not affected by the toxicity of the hedgehog,
Toxopneustes [from *toxo- , Greek pneustēs = breathing heavily], the toxin is also dangerous to humans (slackening of body muscles, respiratory distress and possibly respiratory arrest).
On the internet there is a report about an occurrence from Indonesia, but no reliable sources can be found.
Hybridization between the sea urchin species Toxopneustes elegans and Toxopneustes pileolus has already been scientifically proven, both sea urchins have the same winter spawning season in Okinawa.
Like other sea urchins, Toxopneustes elegans collects various items and carries them on its body, see www.echinoderms.net.