[Kettle of fish]

Mice on stilts. Cheese cubes on toothpicks.
I'm sure we are all aware that sometimes at gatherings, people have plates of nibblies. Often consisting of cheese cubes or tiny bits of sausage - on toothpicks - ala easy to pick up and no sticky fingers.

So look at it from the mouse's point of view. It goes near the cheese, and the cheese cubes start panicing. The cheese cubes probably have sentries or scouts or something to warn of mouse sightings so that the rest of the cheese can scatter and hide. But, aha! Cheese is not very intelligent. So the mouse only has to trick the cheese cubes just enough so that it can get close enough. And it infiltrates the cheese cube community by somehow tricking the cheese cubes that it is one of them. *drum roll*
So it goes on stilts - to mimic the toothpick effect (ok, so it needs at least two stilts - but look at it from a side view. Plus - even with multiple stilts/toothpicks it could just be a mutant cheese on pick.)
Voila!! Cheese on stick costume.

Ok - I blame this on Belin. He started with the lab mouse on stilts image. So naturally I had to figure out why they were on stilts...