What can you catch but not throw?

Why this works

This riddle plays on the double meaning of the word "catch." In one sense, you can "catch" a cold when you become infected with the virus that causes it, but in the physical sense, you cannot "throw" a cold like you would an object. The clever twist lies in the juxtaposition of a tangible action, like throwing, with an intangible concept, like an illness, highlighting the uniqueness of the phrase "catching a cold." It's a fun reminder that language can be playful and full of surprises!