Moon orbits crossing each other Some planets, such as Mars, have 2 or more moons. Giants, like Jupiter of Saturn have a lot of moons!

How likely the orbit of one crosses another one's orbit? Is it possible for two moons to collide? If yes, what would exactly happen?
There is one known pair of moons in the solar system that seemingly swap orbits every couple of years. That's Saturn's Epimetheus and Janus. Their orbits are so close together that they interact gravitationally every couple of years (when the inner moon catches up to the outer moon), so that the outer moon is slowed down, and the inner moon is accelerated.

Each moon changed direction from prograde to retrograde and vice-versa in two co-orbital horseshoe orbits, never crossing paths as they exchange a bit of momentum when closer but Saturn's gravitational pull prevails and pulls each of these two moons back in the opposite direction where they came from, swapping from lower to higher orbit. It's a bit tricky to explain in words:



[From: The Rotation of Janus and Epimetheus - Tiscareno, Matthew S. et al. Icarus 204 (2009).]