How come in videos such as Food Battle where both guys play against themselves, Anthony and Ian don't seem to care about anything that happens to each other, even if that includes the other one outright dying? Because they're used to each other being killed or severely injured, only to be quickly healed, so it's not a huge concern.
Well, that and they hate each other...
"Hate" is a bit of an overstament, but they do get carried away with the challenges.
In the "My Morning Routine" video, all the horrible parts of each of their routines were because Ian and Anthony intended to prank each other but didn't know that one was pranking the other.
At the end of Magic Keyboard! Anthony accidentally closes the entire universe. Not only that, he forgot to save. As in he and the keyboard are the only things left in existence. Think about it.
In Magic Tapeworm! Ian gets a magic tapeworm which destroy things with fireballs. Said tapeworm has the power to destroy civilizations due to an unspecified prophecy. Anthony gets help from a strange Witch Doctor- whose reaction upon actually seeing the tapeworm, was to drinkpoison.
Actually, he drank the poison because Rebecca Black had a CD, which the tapeworm turned his horn into.