Chop is a Rottweiler and it is currently unknown how the player will be able to interact with him in-game, however a pre-release screenshot reveals that he will be able to sit in a car with Franklin, and possibly occupy a seat like other NPCs. In Franklin's trailer, Chop is shown to be attacking a Ballas gang member; leading to the conclusion that he can help Franklin during fights. However, it is unknown if other dogs will do the same. Chop can also help the player to find hidden packages. There will be a throwable ball in the character's weapon menu, allowing you to be able to throw the ball for Chop to catch.
It was said in a interview with a Japanese magazine that Chop can be killed in gunfights. Chop can also be customized. Change the collar color to the player's liking or even give him a bandana if they wish. Unfortunately, this is all unconfirmed and was taken from a source of unknown reliability.