Pissenlit

(un) pissenlit = a dandelion (the 't' is silent)

manger (or sucer) les pissenlits par la racine = to be dead and buried - literally to be eating (or sucking) dandelions by the roots

But the most interesting part lies in the origin of the names:

• The French name, "pisse-en-lit" literally means pee-in-bed, and reminds us of the flower's diuretic effects
• Another French name for the flower is dent-de-lion (literally lion's tooth) because of the shape of its leaves. And, you guessed it, the English name is a phonetic adaptation of this one