When in danger, an opossum lies on the ground and plays dead, perfectly still.
Tips
memory
Read 负 as "to carry on the back", as in 负重: a mother opossum carries her young on her back.
usage
Despite the 鼠 ("rat"), it is no rodent but a marsupial (有袋类动物), the only one found north of Mexico. Its trick of playing dead gave English "playing possum"; Chinese says 装死.
