The Stinging Glow Urchins are sea urchins used in the Toxicity Challenge in Monsters University. The urchins are dark blue, but glow a bright purplish-red off and on. They are highly toxic, and anyone stung by them will massively swell up as if they were a balloon. According to Claire Wheeler and Brock Pearson, the urchins represent human belongings in the game that Scarers are meant to avoid while scaring children, as actual human objects are supposedly too toxic to be used.