Horsetail

Horsetails are items from Paper Mario: The Thousand-Year Door, which are found in an area of Petal Meadows. Just before you reach the area with the bridge, coming from the Rogueport pipe, there is a Candy Cane that, when hit with a hammer, sinks down and bounces back up. After hitting the cane 10 times, a horsetail comes out. You can receive the horsetail as many times as you'd like, after exiting and re-entering the area. They heal 3 HP.

Horsetails also in Super Paper Mario, where they restore 7 HP and cures poison, and are usually dropped by Putrid Piranhas. They could also be bought in the Itty Bits in The Dotwood Tree for 18 coins.