"Fred gave me one of those when I was seven -- it burnt a hole right through my tongue. I remember Mum walloping him with her broomstick."
-- Ron Weasley (PA10)
Acid Pops are a sweet sold at Honeydukes in Hogsmeade (PA10).
Acid Pops have the ability to burn a hole through the tongue of the eater, as Ron discovered when he was seven (PA10).
From the Web
"Acid Pops" on the Harry Potter Wiki