Steve Harmon, a high school student in Morristown, NJ, decides to get back at Winston a classmate who ratted Steve out to a teacher after a prank. Steve's plan is to disguise himself as a clown at a local carnival in order to get close enough to throw a pie in Winston's face. As Steve is about to make his move, Winston and his girlfriend are kidnapped by a trio of sinister clowns and dragged into the Hall of Mirrors. Steve follows them, deciding that saving his friends is more important than revenge on Winston. He finds out that these clowns are extradimensional beings planning a full-scale invasion on Earth. The clowns open up a portal to Dimension X and drag Winston and his girlfriend through. Steve follows after them.
Traveling through the portal activates Steve's mutation, altering his molecular structure, making him rubbery and blob-like. He lands in a cell occupied by the former Scientist Supreme of Dimension X .The scientist, who was imprisoned for opposing the invasion plan, explains that when Steve went through the portal, "rather than having [his] atoms scattered throughout the universe, [he] was molecularly dis-discombobulated. This transformed him into a new form of matter-- a type of living unstable molecules called electroplasm, which is totally indestructible."
The scientist gives Steve two gloves outfitted with "molecular stabilitroids" that will enable him to control the cohesion of his body's molecules. The gloves also enable Steve to carry weapons in hyperspace. He can make the hidden weapons appear at will, as if he simply plucked them out of thin air. The Scientist Supreme then goes on to encourage Steve to use his new abilities to stop the evil ruler of Dimension X . After doing so, Steve rescues the kidnapped humans and returns them to Earth. His best friend Mike Peterson, one of the kidnapees, recognizes Steve even in his newly-altered state. Once Steve tells Mike everything that happened, Mike informs Steve that he has "Just had an origin" and suggests Steve come up with a new name under which he can fight crime. After rejecting several suggestions (including "The Joker" and "The Jester"), Steve finally names himself Slapstick.
source: http://www.angelfire.com/comics/benriely/
http://www.comicvine.com/slapstick/4005-42983/