Literally just a raw onion, often given to pledges of a fraternity. As you might be able to imagine, they taste horrible and burn like hell.
Brother: "I have a present for you, it's a pledge apple!" "Isn't it tasty?"

Pledge: "yes sir"

Pledge: "I ate a pledge apple yesterday and now my taste buds burn"
by Gluc April 20, 2021
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