A tool who is famous, but only on YouTube. Lacking any meaningful talent, the YouTool must continually amp up his level of douchiness to avoid inevitably becoming a has been.
The YouTool is the bro-like equivalent of a hot girl who got instafamous by posting whorish pics on Instagram.
YouTools typically have punchable faces and secretly harbor sexual fantasies about their mostly preteen audience.
Bob: Did that YouTool Jake Paul actually fuck a 12 year old girl?
Louis: The people that live at 1600 Vine are such YouTools.
Bob: I'm pretty sure that YouTool just fucked a 12 year old, but I can't be sure because after he finished he said "it's just a prank bro".