MouseBot is a clever little robot, and has managed to swipe a Security Pass from one of the cats.  You can use the Security Pass to skip a level when you're really stuck.

When you use the Security Pass on the "You Died" screen, it jumps you back to the level select screen and unlocks the next level.

When you use a Security Pass on the level select screen, it uses the pass to skip the most recent unlocked level, and unlocks the next level.

If you want ot skip additional levels, you can purchase additional secuirty passes.  You can also re-claim and re-use old security passes by going back and beating the levels you skipped.