But when they finally tested the weapon, it proved disastrous. Sandy was caught in the explosion, and he mutated into a giant yellow-skinned and red-eyed monster. He had clearly became evil, but just before he was going to crush Sandman, he collapsed to the floor, due to the strain of the transformation.
Sandman knew he couldn't let Sandy go free in that condition, so he imprisoned him in the basement of the townhouse, in a gas-filled glass chamber, where he kept him unconscious for years. Still, years later, Sandy finally broke free from his "Velvet Cage," and wrecked the interior of the townhouse. He then broke out and caused havoc all over York City.