Substance Mimicry (many) – The ability to turn one’s body into several substances. Unlike (415) Substance Mimicry (one) in which the character has a body only composed on one substance.
Absorbing Man (Marvel) can turn into any substance he touches and absorb the substance to become larger (Official Handbook of the Marvel Universe V1 #1).
Amazing Man (DC) can turn his body into a substance with just a touch of that substance (DC Who’s Who #1).
Metamorpho (DC) is a superhero that has this power.
The Nature Elemental is composed of earth, fire, water, air and the fifth element (TSR 2158 Monstrous Compendium Annual Volume 2).