So, naturally, I went forward and looked up the domain information for both TentacleGrape.com and MnemosyneLLC.com, both of which have the same phone number attached to them. (MnemosyneLLC.com also has a name, Julie Howe, in its registration info.) But the phone number is no longer in service.
Now, Tentacle Grape isn't Mnemosyne LLC's only project-- the company's site also displays a button for something called LOLCattz, which appears to be a defunct card game, and one for Rubies of Eventide, an MMORPG that the company published in '03. This game seems to still be running, because I haven't found anything about it being offline...although the official website is more or less broken now.
Sounds a little skeezy so far! I've sent an e-mail out to the address in the WHOIS info for Tentacle Grape and Mnemosyne, and at least neither has bounced so far-- I'll give you a heads up if I get more info. (Damnit, I wanted to try Tentacle Grape...)