Dormouse
These gross little cuties have a one-time-only get-out-of-death trick that has helped them evade many a mousetrap. When the dormouse gets it tail caught in something the skin on the tail will come loose and fully detached from the rest of the body, allowing the mouse to escape. This trick leaves an exposed tailbone that the mouse will often gnaw off because the skin never grows back.
Source: https://en.wikipedia.org/wiki/Hazel_dormouse