Originally, Sunspot's superhuman power was limited solely to superhuman strength and enhanced durability, and then only in his solar form. Unlike many superhumanly strong heroes, Sunspot was unique in that his physical resistance to impact only increased somewhat when he employed his superhuman strength, and he was not bulletproof by any means. The phrase, "Careful Bobby, you're strong, not invulnerable!" or variations was seen many times. In addition, Sunspot's powers have radically changed and grown since the character was introduced; he can now withstand the force of a speeding eighteen-wheeler traveling at speeds of 100 mph, alongside surviving an A.I.M explosive charge latched onto his side.