Sucker

The Sucker is an item in Great Pumpkin Island. It's lemon-flavored.

Pig-Pen will give you this item after you give him the Trick-or-Treat Bag. You must then give the Sucker to Linus in exchange for the Party Invitation.

Trivia

 * There is a quote from the island, the old comic, and the TV episode referring to the Sucker: "Never jump into a pile of leaves with a wet sucker".
 * Sucker is another name for a lollipop.