Originally, he is from the AWOW (A World of Wacky) mod made by weigiesen. In the mod, Mr. Geck was one of the many enemies that you could fight in the mod. However Al made Mr. Geck friendly to him using the G.E.C.K. Sadly Al forgot to set him as friendly to all other NPCs and in consequence, this made all other NPCs attack Mr. Geck.
During the mod review, Al needs to find a house for him and his companions to live in (other than in Doc Mitchell's house which they are currently living in) and calls upon Mr. Geck to find a large house for Al and his companions. Sadly, Mr. Geck is a very cheap person and sells people very tiny homes that most of the time are made out of dumpsters with radios that cannot be turned off in anyway, and Al is unhappy with what Mr. Geck tries to sell him.
Mr. Geck dies multiple times while Al tries to keep him alive (not knowing what he was about to sell) by using the Groovatron mod to move him away from the NPCs that are shooting him and his one time use time machines(that are really just quicksaves). In the end however, Mr. Geck was put down by Westside Guards and Al gives up on trying to keep him alive, and he dies before part two of the mod review. It is unknown if he will make another appearance.