And out of existence.
Nope. In fact they stop in midair after smashing into each other. Its just one big block with some spikes sticking out of it.
Just re-watched the twins scene and I gotta say it is easily the best of all the post-credits scenes. So creepy and has an epic foreboding of things to come.
Getting to see Baron Strucker, QS and SW in the flesh for the first time was awesome. I was debating whether this is more geektastic than the reveal of Thanos and I think it is because we get to see them using their powers.