A Grave Mushroom (ハカバテングタケ Hakabatengutake ) is a magical mushroom that can only grow in the graveyards. These mushrooms are necessary for spiritual techniques to call the souls of the dead, although its effects should wear off by sundown.
The Grave Mushrooms are small red mushrooms with a skull face on its surface. It's rather a medium size for a mushroom and can be used in potions because it's useful in making posionous potions.
Sucy plucks a Grave Mushroom from a graveyard, which is accidentally combined with Akko's object restoration spell to bring Mr. Holbrooke back to life for a day. Mr. Holbrooke then runs around trying to find a man he says is horrible, then realizes it's himself. He reunites with his daughter by the end of the epsiode, proud that his daughter acomplished so much.