Inside Leviathan

You've been swallows by an absolutely gigantic gyarados! This gyarados is at least a dozen times the size of a normal gyarados.

Your first destination is the stomach, whose living walls shift violently, making it virtually impossible for bipedal creatures to stand. It's almost hot enough to boil water. The walls seem to be virtually impervious to harm, and forcing your way back up the throat is absolutely futile. A pool of acid waits at the very bottom, and lesser amounts of acid cover every square inch of the belly. The skeletons of past victims, some even human, decorate the stomach. Various living pokemon attempt to fight their way out, but it is utterly hopeless for them. You are likely to fall directly into the pool of acid upon entrance, however digestion itself takes at least an hour to kill. In various directions are sphincters, fleshy doorways into other organs of the body.

The sphincter at the very bottom of the acid pool is not recommended.

You'll need to explore the body in search of some way out if you want to avoid your gruesome fate. There are no organs that can't be reached via the various doorways within the body or the blood stream. Beware, the clock is ticking.