Joseph Smith is a trained boxer, wrestler and actor who was mutated by a chemical accident. He first appeared in "Amazing Spider-Man" vol. 1 #38 (July, 1966). When his powers are active, Joe demonstrates superhuman strength and durability, able to lift c. 10 tons (in Spider-Man's range strength-wise). He is an unexceptional combatant while calm but the resurfacing of his powers often leads in a violent rage, going into berserker rampages. His powers resurface at seemingly random intervals and then fade away. He has no control of the process. However in "Captain America" vol. 1 #246 (June, 1980) his powers surfaced due to his emotional pain at the death of his son and he went into his most violent rampage to date. Pointing to his emotional state having an effect on his powers.
When not having his powers, Joseph remains a physically fit individual but his combat skills are rather poor. Trying to face Mysterio without his powers got Joe defeated in less than a minute. He has remarked that his boxing and wrestling career ended because of being knocked out too early during his fights.