This ThunderCats t-shirt shows Mumm-Ra the Ever-Living standing over the heroic characters Panthro, Lion-O, Cheetara and Tygra. In ThunderCats, Mumm-Ra is the leader of the Mutants of Plun-Darr, a race that is trying to steal the ThunderCats' Sword of Omens. The ThunderCats battle Mumm-Ra and his mutants in each of the action-packed episodes from the classic animated series.