All of these replies are hillariously misguided.
- Get others to help kill him?
- He's bad late game?
- He'll give up?
As a Singed 1 Trick Pony, I climbed into Gold during the height of Singed Proxy madness.
A proxying Singed tells his midlane "If your opponent leaves to chase me, push your lane like you're giving birth" The Singed player is also doing that sort of crap to keep the jungler top. He tells his Jungler "Camp Bottom, and Camp Mid and snowball them. Even if I lose, I can come back and farm hard once I get a couple of core items"
So suddenly, his strategy is to purposely lose his lanes, to help his team win 2 lanes, and he can still make a huge difference late game. So how do you deal with a proxying Singed?
Let him proxy, and tell your Jungler, to clear his way up and gank later as his normal path. Don't let your teammates leave their lanes, don't let your Jungler just leave what he's doing because he see's a Juicy Singed being an idiot between the top 2 turrets. And for the love of god, if you and your jungler pinch him, and he gets away. don't chase him forever. go back to your lane, re-set it... and use the re-set minions to try to push to his tower. If he's back behind your tower, continue to farm hard, and you'll carry as hard for your team, as he'll carry for his.
If you start chasing his ass around, and using your Jungler top all the time to pressure him, you're playing into his game, and you'll lose in the next 20 minutes and have no clue why.