A boxing glove owned by Sam & Max is occasionally used in Sam & Max Season One to knock various people out of hypnosis. Jimmy Two-Teeth has a boxing glove just like it which he uses to give him an edge in his boxing career (since his opponents use mere rat-sized gloves). Since both parties are prone to misplace their glove and time travel is involved, it is unclear if and to what extent these two gloves are actually one and the same.
Sam & Max' glove is first seen in Culture Shock, where it is used to knock out the Soda Poppers. It is then misplaced for a while, to be found again in Abe Lincoln Must Die! (where it is used on the Puppet President). It may be important to note that it is found right next to the pond Jimmy Two-Teeth is relaxing in. The glove is kept in Reality 2.0 (where it proves quite useless) and lost again in Bright Side of the Moon. At the end of Bright Side of the Moon, Sam takes out the glove and gives it to Max (in order to knock out everyone on earth), saying he'd been keeping it for a surprise.
In Ice Station Santa, Sam and Max end Jimmy's boxing career and take his glove. They then travel back in time to the time The Mole, the Mob, and the Meatball took place. There they find Jimmy lamenting the loss of his boxing glove, claiming Sam & Max took it. They then drop the glove they took from him in the future at his door. Given the way time travel works in Ice Station Santa, this intervention should already be part of the original timeline.