So, in honour of the miracle of the puffball:
The Fungal Curse of Tribhuvan
Level 8 Magic-User Spell
The archmage Tribhuvan was of a particularly vengeful and malevolent nature. So when, after falling in love with Asha, the beautiful daughter of the headman of the village of Gyamotang, he was refused her hand in marriage, he spent 33 cycles of the moon creating a spell which would bring him the satisfaction of revenge.
The Fungal Curse, when cast, affects a single mushroom, toadstool, or similar, and ensures that all of its spores reach adulthood. Whether this is through making the spores invulnerable, or simply manipulating their destiny so that, miraculously, none are eaten or destroyed, is unknown. The effect is that a vast area quickly becomes overwhelmed with fungus.
After casting the spell, within 1 week the hex in which the spell was cast and d4 hexes around it are covered entirely in fungus. This kills all plant life and makes the area uninhabitable - likely permanently.
Tribuhuvan himself never used his spell. After threatening to devastate Gyamotang and the area around it, Asha agreed to marry him. The unfortunate story of her children is, of course, well known.