First item on list Craig developed a stinker? (6)

I believe the answer is:
garlic
'first' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for garlic that I've seen before include "Pungent plant" , "Pungent bulb feared by vampires" , "Culinary bulb" , "Plant of the onion family" , "Pungent allium" .)
