A horrible deal that even an idiot could understand is not worth the risk. It's also a well known card from Hearthstone that gives the opponent the ability to play all the spells in their hand for free.
Dude, don't fuck with that hoe, she a millhouse manastorm, not worth it.
Someone or something that bites your ankles.
To a postman, an ankle biter is often known as a dog.
To an adult, an ankle bitermay be a toddler.
To hikers, an ankle biter is sometimes a tick.
And so on.