From the Super Mario Wiki
A Jelly Ultra is the most valuable type of Mushroom in the Paper Mario series. The only possible way to obtain one is to mix a Jammin' Jelly with an Ultra Shroom with Zess T.'s or Tayce T.'s cooking ability. If the player has used all of the Jammin' Jellies and Ultra Shrooms that are hidden in the game, this item is very expensive to make. Available from Charlieton for 120 coins each, or in the Deepdown Depot for 200 coins each, both ingredients are costly to buy.
A Jelly Ultra appears to be a green-capped mushroom with bright yellow jelly poured over it. They restore fifty HP and fifty FP. This is a good item to have if either Mario or his partners can not use the Double Dip or Triple Dip Badges. Other than that, it does the same thing as one Ultra Shroom and one Jammin' Jelly, just in one turn, rather than two, saving the player some time to attack.
If the player were to sell a Jelly Ultra, they would receive 150 coins.
Names in Other Languages
||Fungo Reale U
||Ultra Royal Mushroom