Decay was a fictional elderly mutant

Mutant (Marvel Comics)

In comic books published by Marvel Comics, a mutant is an organism who possesses a genetic trait called an X-gene that allows the mutant to naturally develop superhuman powers and abilities...

 from Marvel Comics

Marvel Comics

Marvel Worldwide, Inc., commonly referred to as Marvel Comics and formerly Marvel Publishing, Inc. and Marvel Comics Group, is an American company that publishes comic books and related media...

 who first appeared in Quicksilver #8.

Fictional character biography

Decay was recruited into the Acolytes

Acolytes (comics)

The Acolytes is a team of comic book mutant supervillains in the Marvel Comics universe. The Acolytes followed the principles of the mutant Magneto, particularly the mutant right of superiority over normal humans. Some members of the Acolytes even worshipped him with a religious fervor and regarded...

, a group of mutant terrorists

Terrorism

Terrorism is the systematic use of terror, especially as a means of coercion. In the international community, however, terrorism has no universally agreed, legally binding, criminal law definition...

. Decay possessed the ability to drain the life force of others to boost his own failing health. When he did so, the person he had drained would crumble into dust.

Decay was probably the oldest member of the Acolytes. He was killed when he overloaded his powers trying to drain the super-enhanced High Evolutionary

High Evolutionary

The High Evolutionary is a fictional character that appears in comic books published by Marvel Comics.-Publication history:The High Evolutionary was first mentioned in The Mighty Thor vol. 1 #133 , and first appears in The Mighty Thor vol. 1 #134 , and was created by Stan Lee and Jack Kirby...

.