Coal

Coal is an item with no use. It can drop from Presents obtained during the Christmas seasonal event, with a chance of in pre-Hardmode and  in Hardmode and also has a  chance to be dropped from Jungle Mimics only in worlds with the seed celebrationmk10.

Trivia

 * In a now-humorous tradition, parents in Western countries would classically threaten to give only to children as their Christmas gifts if they misbehaved, hence this item dropping from Presents, along with its tooltip.
 * Unlike other "junk" items like the Tin Can or Old Shoe, Coal has a rarity of instead of.