This guy keeps blackmailing me into friendship through suicide threats. WTF?

K, so this guy is really weird and annoying, so don't start saying "You should be nicer" because I'm literally the nicest guy in my year to him. But now he's clinging on to the kindness with a vice-like grip. He keeps asking me out places like bowling, cinema, etc. He even invited me to his house to play gamecube! He has no ps or xbox. I've realised now that I have to distance myself because he's becoming obsessive, so I ignore his texts, (yes I gave him my number stupidly), but then when I ignore his texts he says, "Ok fine, you may not see me again". How do I end this without him killing himself?