The Nuke Block is a block that if the wheel touches it, Flash Player may crash on lower end computers.
It is more deadly than any spike, despite not actually being one.
It the only block that can freeze the game.
It is created by using a lot of finishes, until the block turns white, using The Void glitch blocks.
It looks very similar to the Anticolor Lock, but the nuke has a hazy outline, whle the anticolor lock is solid (in the Trackmill version). Take care!
See this level to see the block in action, along with a block with similar consequences but not full-out crashing the game.