Goat

The Goat is a hollow-horned, bearded mammal, originally of mountainous areas. Although it hasn't been seen in many episodes thus far, it played a major role in Walk Like An Egyptian - Part 2's challenge.

Hook, Line, and Screamer
After Owen fell off the edge of the cliff, the goat made a cameo, being hit by Owen. Other than that, the goat made no other appearances in Total Drama Island.

Riot On Set
Gwen mentioned that she had a petting job at the zoo and she had to clean up after the goats. In the same episode, Duncan, while acting, mentions a goat his character had in their youth.

The Aftermath: III
The Goat appears very briefly in The Aftermath: III, when Owen is mentioning all the bad things he's done, he mentions stealing his Uncle Max's toupee and gluing it to a goat's bum at the petting zoo.

Walk Like An Egyptian - Part 1
The goat was a prize for Team Chris Is Really Really Really Really Hot. The goat appears to be quite aggressive, because as soon as Chris introduced it, it charged towards Tyler and knocked him out.

Walk Like An Egyptian - Part 2
Team Chris Is Really Really Really Really Hot somehow is able to perfectly balance their team on the goat despite its small size ompared to the team. The goat is able to move the group across the desert and they are the first one to make it to the Nile River. The goat seems to have a very good relationship with Alejandro, as the goat jumps into his arms while they paddle across the Nile. Becuase Team Chris Is Really Really Really Really Hot is able to keep the Goat for the whole challenge, the team is safe.

Slap Slap Revolution
Chris orders a vicious, rabid goat to attack the contestants. But before it attacks them, it must first face off against one of the local goats, which is much bigger and seemingly more ferocious than it. In an instant, the small and cute one eats the larger one, then turns to attack the contestants. During the challenge, it attacks Team Victory and Team Chris Is Really Really Really Really Hot. LeShawna helps Lindsay to avoid its attack, while DJ catches him. He holds him in the air and the goat hits a tree branch that they pass under, and gets left behind.

Aftermath: Revenge of the Telethon
The goat was seen in a segment called "DJ's World Of Animals". DJ tries to pet the goat but ends up hurting itself from trying to break free of the cage. Once Blaineley sets them out of their cages, all of the animals attack everyone in the studio to raise money for the show, with the goat ultimately attacking the camera after attacking Geoff.