Behold, the Mortiverse:
http://www.enworld.org/forum/2873260-post1.html
Someone asked the question "What's the highest challaenge rating creature there can possibly be?" The response? The Mortiverse, the most powerful creature possible. How strong is it? The damage it does is written in scientific notation.
How do you kill it, you may ask? Well, firstly, you must reduce it's health to 0, which is no small feat given that it has 1,584,563,250,000,000,000,000,000,000,000d1000+ 627,710,173,312,402,500,000,000,060,213,403,500,00 0,000,000,000,000,000,000 HP, and the fact that it regenerates at a retarded rate, and especially since it has a crap load of other skills and generally how powerful it is. Then, you need to use Wish or Miracle to finish it off, and the Wish/Miracle must bypass its Spell Resistance, which pretty much means that the Mortiverse needs to roll a natural 1 on its save. Even if you do kill it, when it dies, it implodes in on itself, and sucks anything within its reach (LOOOOOOOOOOOOOOOOOOOONG distance) into a void unless you make a reflex save of 831,895,706,300,000,000,000,000,000,108.
As for physical qualities, it's about half as big as the known universe, and is classified as a Octodecaogdoad Nona-Macrobe Amidah Apocalyptic Black-Hole-Spawned Legion Elder Unelemental.
Best. Monster. EVAR.