It is a beetle pupa(plural = pupae)- one of the stages through which these animals go on the way to reaching a stage at which sexual reproduction can take place. One of your mealworms has pupated. Most insects(such as beetles hymenoptera, butterflies,etc.) have this stage but many skip this stage (like roaches, cicadas, dragonflies, etc.) Not sure about superworms because there is some sort of process used to make tem bigger, but if you leave it alone in the mealworm conainer it should eventually shed the outer shell you see it in now and emerge as a beetle. Giant mealworms(different from superworms and common mealworms) will not pupate unless they are separated in a container by themselves - a sort of evolution derived behavior designed to minimize predation by fellow mealwoms during the vulnerable pupae stage . We raise giant mealworms( along with roaches and crickets) and in order to keep the colony going, we have to take regularly separate some of the older (ie. largest) mealworms from their mates into a plastic container with many separate compartments to induce pupation) Once the animal metamorphisizes into the beetle, it is replaced into the container with the other beetles/mealworms. You don't have to do this with regular mealworms - the pupae can be left in with all the rest. Owchams at gmail.com