The Guinea Pig is a pet summoned by the Cabbage. Once the player has reached a certain distance from it, it will teleport to the player by flying and leaving a trail of clouds behind it. The Cabbage can be found in surface and underground chests at any time and seems to be more common in Jungle biomes in the Xbox 360 version.
The Guinea Pig is the only pet to not be based off of a monster that already existed in Terraria prior to its implementation as a pet.
The guinea pig depicted in the game seems to be based off of a real life breed of guinea pig called a silkie.
In the Mobile version, a Guinea Pig can get stuck in blocks while trying to get to the player when flying.
In the Console Version, the Guinea Pig can be shared between two or more players by spawning the Guinea Pig, then throwing the item to the other player and then him/her can spawn it also without despawning the other player's, this can be repeated again and again.