Vac-Man may sound like the name of a door-to-door vacuum salesman but it's actually the name given to Stretch Armstrong's nemesis, who is pretty boring as villains go and therefore didn't sell very well.
But on paper Vac-Man's toy action sounds pretty sweet:
Unlike the Stretch dolls which contained a syrup-like liquid inside a rubber sheath, Vac-Man (and associated models like the Vac-Pac which were the heroic enemies of Vac-Man) contained a grainy solid, produced from ground-up corn cobs. By attaching the provided pump to a socket on Vac-Man's head, air could be sucked out until the body became rigid. It could then be stretched, but unlike Stretch Armstrong, it would retain its stretched shape until air was let back in. -Via Wikipedia
His name and his cool vacuum power made him highly requested by The Action Lab's viewers, and they discovered the vacuum chamber had an oddly satisfying effect on Vac-Man's corn cobby body.
-Via Laughing Squid