Maxperson
Morkus from Orkus
In practice, I don't think the cheese methods would actually work, due to a combination of movement and reach and readied actions. A low-level Fly spell would wear off before anyone could kill the Tarrasque, and it's not just going to stand there motionless while you try.
Yeah. It requires a white room where the Tarrasque just sits there and lets you beat it to death. It doesn't work in game play.