Thorn beast

Thorn Beasts are used as food by the Covenant and Jiralhanae in particular. They are docile herd animal. There neck and head contains a high concentration of neurotoxins. it is unknown what causes this or what function it has for the animal.

Some could be seen in the halo graphic novel as infected by the Flood. Because they serve as food they most likely where kept at the agricultural ship Infinite Succor. However, this is only speculation.