Tommy Tribbles, better known by his hero name Gastric, is a student hero with one of the strangest mutations imaginable: an impossibly powerful stomach. He can swallow and safely store objects or people of virtually any size, regurgitate them unharmed, inflate his belly at will, alter the acidity of his stomach to contain or dissolve nearly anything, unleash stomach gurgles loud enough to disorient opponents, and use his nearly indestructible belly as both a shield and a battering ram.

Despite possessing one of the most bizarre powers on the planet, Tommy is remarkably laid back. He rarely panics, enjoys joking about his own abilities, and prefers solving problems creatively rather than through brute force. Unfortunately, even a super stomach still has ordinary stomach problems. Heartburn, nausea, indigestion, upset stomachs, and diarrhea remain his greatest nemeses.