Rune started limping for no apparent reason
Not bleeding so it wasn't something sharp hidden in the grass. There was no "I just hit something" squealing earlier. Nothing stuck to the leg/foot. The usual tricks to make him forget that it hurt earlier not working either
Turns out that there was a spiky leaf stuck to the end of his tail that he somehow managed to keep stepping on with just the left foot 🤦♂️
TL;DR:Something wrong with the leg? Check the tail