Bulge had the roughest growth spurts growing up. It did nothing to prepare him for the surprise awaiting him in adulthood. One day, Bulge woke up and noticed his left leg was about three times it's normal size. After the panic attack faded, he stared at his leg while waiting for an ambulance. Slowly it "deflated" back to normal. He gradually found that he was able to control the size of his leg. Then any part of his body.

Strength
Can explosively inflate and deflate any part of his body.

Strength Source
Innate ability.