Variant spelling and pronunciation of "tentacles" based on some obscure Icelandic language (see tentakelporr, tentakel beast, Yggdrasil Proteus).
1. Used to note that the tentacles in question are doing fucked-up shit (see hentai), as opposed to, for instance, a plate of calamari that really doesn't do anything. This is done both so that casual observers won't be able to tell what you're talking about, so that otaku, daemonettes and twodephiliacs won't overhaer you and mistake you for one of their own, and so that harmless tentacles (yes there are a few left) do not become Brondonized.
2. MCC Anime Club's favorite thing in the whole world.
3. My current Nemesis (although I am still have been without an Arch-Nemesis since 2003)
Dumbass A: I don't know how anyone could get off to hentai! It's frikkin tentacles!
Dumbass B: I know, it's disgusting!
Otaku Jackass: Tentacles?! Did someone say tentacles!? Here's some tentacles *shows Dumbasses Sailor Moon tentakelporr*
Dumbasses: Noooooooooooooo!!1111one *vomit*
Me: Why must the tentakels hound me to the ends of the Earth?! Do I look like a Japanese schoolgirl?! *doesn't look like Japanese schoolgirl*
Zach: *shudders* I don't know. I don't know why the porn shop I work at carries shit with tentakels either.
*Otaku Jackass walks by engrossed in Sailor Moon pr0n*
*Zach smacks Otaku Jackass upside the head for not returning his pr0n to the store on time, causing him to drop his Sailor Moon pr0n into a nearby volcano*
Otaku Jackass: Nooooooooooo!!!!!!1111one *jumps into volcano after Sailor Moon pr0n*