A Big 1-UP sticker.
Big 1-UP is a Battle Sticker seen in Paper Mario: Sticker Star. Whenever Mario uses this sticker, his HP will gradually heal over turns. This sticker is extreamly rare and can only be found in one level: Drybake Desert.
The Big 1-UP sticker is extreamly similar to 1-up Mushrooms in color. However, Big 1-UP sticker only heals Mario's HP rather than bringing him back to life.