There are two spells named cocoon. Both are Druid 8th level spells.
1) One is in the Spell Compendium. It is a crappy improvement on Gentle Repose / Reincarnate. (not even worth 6th level)
2) One is in Magic of Faerun. It eats people, and gives you (some of) their power. It is referenced in PGtF.
I care about the Faerun one. Was it ever actually reprinted in any 3.5 book?
And yes, I realize that the PGtF is the 3.5 update to all 3.0 FR books, and the fact that it is referenced there w/o any update means that it is good as is. I am just seeing if there is a reprint of the spell anywhere.