Peter Packrat was a game in which the title character explored one of three types of stages (junkyard, sewer and tree) and collected shiny objects to take back to his base. All three types of stages are basic at the beginning of the game, but as the player progresses to higher levels the stages become larger, more complex and nearly overloaded with the various enemies who, for whatever reason, want to stop Peter from completing his collection.
Peter, luckily, can toss any objects he's carrying (including three rocks that he keeps in his backpack) which will fly back to him after connecting with an enemy (downside: if the object doesn't hit an enemy it won't return and Peter has to go and find it). Stunned enemies will remain out of action long enough for Peter to get away (although certain enemies, like bats and owls, could actually be ridden for a short time, allowing Peter to leave the area even faster). In true form for a packrat, Peter is an excellent jumper and a smart player can use his jumps to great advantage when fleeing from foes.
Bats and owls aren't the only creatures that chase Peter. The junkyard stage features an obviously fowl-tempered bulldog, the tree features cats and snakes and the sewers include a giant spider and even a crocodile (who gives a couple of Groucho-lifts of his eyebrows if he succeeds in eating Peter). A gang of rats is also after Peter, and they walk around in true gang style with their hats over their eyes and their hands shoved into their coat pockets.
Peter can't take much abuse. In fact, he dies instantly if an enemy touches him (he literally seems to disintegrate, which I always found a bit creepy). Part of the challenge of the game is collecting all the objects in the stage within the time limit without once being tagged by the ever-increasing enemies. The rest of the challenge comes in actually FINDING the required objects, which are usually placed in very inconvenient spots. Worse still, in later levels Peter begins without even the rocks in his backpack and thus he begins those stages totally defenseless until he finds an object.
I played this game a lot back in its day. It disappeared from the arcades I frequented rather quickly, but before it did it was my main arcade game (this was before the Ninja Turtles arcade game came along). There was a time when I actually became quite skilled at it and I was able to get pretty far in the levels before the speed and sheer numbers of the enemies overwhelmed me. I liked Peter as a character too; he had a nice happy-go-lucky personality. Maybe the enemies were after him because he took objects without leaving anything in trade (real packrats typically leave something in the place of the shiny objects they take, such as an acorn). It was a really fun, challenging game. I can't say I have the bragging rights that come with completing the game, because I never completed it. I'm not sure if it's one of those games that COULD be completed. It was never released to a home console (to the best of my knowledge, anyway) so I never found out.
It wasn't Pac-Man, but it was a good example of a Pac-Man kind of game that didn't mind changing a few of the rules.