Yo dawg…, etc. We've seen the classic PC shooter Doom hacked and modded to run on everything from an ATM to an Android Wear smartwatch, but this tops them all. A modder going by the name The Zombie Killer on YouTube has managed to get Doom to run inside of Doom. Yes, really. You can walk up to a computer terminal while playing Doom, and from that in-game machine start playing Doom. No word yet on how deep the rabbit hole really goes.