Right, so far we've been relying on the assumption that you are an omnipotent cosmic being. This is fair assumption to make as your plans involve things like "destroying the universe". However, it's time to get a little more personal here. Grey Goo is the term given to a hypothetical apocalypse scenario that involves self-replicating nanotechnology. Although, admittedly, it's beginning to look slightly less hypothetical now. Anyway, the idea behind Grey Goo is a swarm of nano-bots that are capable of using the resources around them to self-replicate and essentially reproduce. Imagine that just one of these little bots is floating in a test tube of chemicals in a lab. This little guy copies itself in, say, a minute. Then there are two bots that do this, extracting the material from their surroundings, breaking it down and rebuilding it into copies of themselves. These two bots then become four, then eight, then sixteen and so on. Leave this hot mess to stew for just an hour and you get something like 1.15x10^18 (1152921504606846976) little bots. By this point, the bottle of chemicals that they were floating in will have probably run out, but that's okay because they have since broken down the glass that contained it, the lab it was sat in, the scientists in that lab, the town, city, country and eventually the planet on which they began. After a day, you get 3x10^433 (that number is too big to write out, but click here to see it written out fully) which is significantly more that the number of atoms in the observable universe. Of course, space is made of a whole lot of nothing, so they might be unable to travel through space quickly enough to sustain the new nano-bots being built - that's if their combined mass collapse into a black hole first. In fact, even if the nano-bots could travel outwards at the speed of light and only weighed 1 nanogram each, then the density of nano-bots will be large enough to create a black hole after 161 mins (credit goes to my friend Teggers, who is a certifiable genius, for figuring all this out). If this was your plan they you could always equip them with little faster-than-light rockets before they mulched your wriggling corpse for fuel, then the universe is definitely doomed.
