Venomous breath or bite poisons pastures

Tarasque

Its breath was believed to be so toxic that it could wither crops and poison the air

Kaliya

some accounts add that his mouths breathed fire and smoke, further poisoning the surrounding land, killing fish, birds, and the trees along the riverbank

Loathly Worm

The princess Margaret was turned into a loathly worm by her stepmother the queen and banished to the Spindleston hills, where her poisonous breath blighted the country for miles until the people feared a permanent wasteland.

Lavellan

Its supposed ability to poison pastures and wells with its venom reflects the deep-seated anxieties about contamination and the vulnerability of vital resources.

Nuckelavee

Its breath is said to wilt crops, poison livestock, and spread sickness among humans.