This ominous short story set aboard a doomed German submarine during World War I was written by H.P. Lovecraft in 1920 and published for the first time in 1925 in Weird Tales. There are any number of things in it that could be presented in game terms, including the caricatures of the Prussian naval officers that appear in the story, the huge and menacing being that inhabits the title structure, and the omnipresent sinister dolphins. The first, however, would be of limited value, the second would likely be of value only in a high-level adventure and require an awful lot subjective extrapolation (i.e., need to pretty much be made up from whole cloth or from references in other works), and the third can quickly be accomplished with the addition of the Fiendish template to a set of dolphin stats. There is a single concrete and esoteric object in this story, however, that serves well for these purposes, and that is strange statuette of a youth that is found on the person of a dead sailor, and my interpretation if it appears here. 

Delphinic Talisman

This is "a very odd bit of ivory carved to represent a youth's head crowned with laurel." It bestows upon anyone carrying it a +5 circumstance bonus on any skill checks pertaining to dolphins, including Bluff, Listen, Sense Motive, Spot, and Survival, as well as any Knowledge pertaining to such creatures. Given the opportunity, however, normal dolphins will attempt to effect the drowning of the person carrying the Delphinic Talisman, which will activate its true and most profound function. If the possessor of the item is, in fact, drowned by any means, he will be reborn 24 hours later as a Merfolk, just as if this had been accomplished with the spell Reincarnate. He will no no longer have the talisman in his possession but even if he should ever acquire it again it will no longer function for him in any way.

Moderate transmutation; CL 15th; Craft Wondrous Item, Reincarnate; Price 8,200 gp.