The wall of STEEL!

I'll be a continent away and 50-175 metres underground. I use the Large Hadron Collider to create microscopic black holes that don't disappear but begin to grow. The wall, nor the dragon can escape the black holes and are ripped apart. If the steel wall finds a way to escape the pull of the ever growing black holes, I'll have already created more black holes in it's intended escape routes. It has no chance of getting out alive. Everything, including the ground the wall was built on are ripped apart among all the black holes, there's nothing left. Not even light itself survived, not even Magus to try to update the wall's status or the wall's escape/attack plan. It's all gone. The Collider worked just as I intended it to (creating black holes), I didn't die before the machine went off, and the black holes didn't die out until after the wall is completely dead. There's no YuGiOh cards that survived either. So no Monster Reborn, no take backs, no do overs, no practice runs, and there's no home free. The steel wall kills me only AFTER the black holes were already created. It's too late for the wall, it can't destroy the black holes in any way it tries. Even if the wall created more black holes to eat my black holes up, the black holes the wall created will kill the wall too.

And if he tries to zombify (a magic card) the wall, I'll just counter it with the most basic counter spell.