Time travel
From Sam & Max Wiki
Sam & Max have used a variety of means of time travel. Trips to the past usually result in history being changed in blatant ways, which Sam & Max aren't very concerned with. Curiously the opposite is true in Ice Station Santa, where the time travel seems to be predestined.
In the video games, other episodes are visited offering a different perspective on things and in one case even changing history to be different from what was seen earlier.
