You can actually Smite the Teemo Boss in Doombots for easy true damage. You can smite all the monsters and minions pushing toward your nexus as well. For an easy win, make sure everyone brings Teleport and Smite and play the following champions:
When Devil Teemo Boss spawns, just repeat smite it and pelt it with your high damage abilities and you should finish him off rather quickly.
I played 
and we did pretty well, poison killed Boss Teemo :D
?
No 
? Extremely high AP sustained damage and easy 2v1
good too
I tried Varus. For a level 100 Run he's garbage. If you farm really well and get a tear/ARP you can get somewhat decent poke until around level 8 or 9, but then you may as well be tickling them with a feather duster.
R & E are good against the bots, especially when they group. Q is good when a melee bot gets too close or when you need to help save an allie or secure a kill. When Teemo spawns Fiddles W provides decent damage while providing sustain from most of his damage.
I've seen to 1v5 Doombots.
