Snake

Snakes are an animal that is venomous in some breeds.

The Questing Beast has the head of a snake and the body of a cheetah.

History
The knight Valiant owned a Serpent Shield painted with three snakes that were magically enchanted to come to life on command and strike an opponent. (Valiant)

When Merlin, Arthur Pendragon, Guinevere and Morgana rode to save Elyan from Cenred. Merlin used magic to influence a passing snake to spook Morgana's Horse, causing Morgana to be tipped off and sprain her ankle, thus making her not in any good shape to make a move against Arthur. (The Castle of Fyrien)