This mule has a bad temper and kicks out at the slightest thing.
Tips
usage
Literally a mule or horse kicking backward. Said of a person, it is someone who has had enough and suddenly refuses: a worker who quits, a child who won't sit through another lesson. It can split around 了: 尥了个蹶子.
mistakes
蹶 has this third-tone reading only here. Elsewhere it is 蹶, as in 一蹶不振 'never to recover from a setback'.