Initially a high school kid smitten with Dee, then a reverend, then a cocaine-addicted street urchin.
Rickety's real name is Matthew Mara. He got the name "Rickety Cricket" in high school because of his leg braces. In high school, he suffered much punishment at the hands of Mac, Dennis, and Charlie who would put their balls in his mouth when he passed out at parties and would take pictures. The pictures would be very popular around school. He also suffered from differing types of torture from Dee. Both Dee and Matt were in physical therapy, the only two in that class. Matt was in love with Dee, but she mostly ignored him. She once made him eat a whole horse turd after promising to kiss him. She didn't end up kissing him, saying his breathe smelled like shit.
He got past the torture of high school, eventually becoming a priest. In the episode "The Gang Exploits a Miracle" Mac discovers a water stain that looks like the Virgin Mary. The gang uses this to get much media attention, bringing Matt back in contact with the gang. Dee completely forgot who he was, but soon fell back in love with him. She confessed his love to him, causing him to give up the priesthood. She had moved past this and no longer loved him.
When we return to Matthew's life late in season 3, during the 2 part episode "The Gang Gets Whacked." Dee and Charlie try to use the now homeless Rickety to sell cocaine. He initially refuses, but later agrees after Charlie promises him a spot at Dee's apartment (without her knowledge of course). Rickety comes back to Dee's apartment with a big score of cash, looking to move in. They instead give him more drugs to sell. He sells them, but also takes some for himself. He wastes all of the money he earned on two "kettle drums" (trash cans) for a musical he's writing about an archangel. He practices in the bar when the mobsters come in looking for their money. They get the money, but find out that one of Pussy Hand's (Mac) friends tried to sleep with his wife. The gang collectively blames Rickety. He gets his legs broken and is put back into the leg braces.
In the season 3 finale "The Gang Dances Their Asses Off" Rickety returns with his leg braces to the dance marathon, hoping to win the bar and ruin the gang's life like they had his. He plots with the Waitress to take them down. His mechanical leg braces make him out to be a formidable opponent, but after challenging Dennis to a dance off, his hardware almost immediately fails and he is eliminated. He then starts to help Frank, who was also eliminated, to sabotage everyone else. He eventually lends Mac his exoskeleton to help him in the competition.