OK, this is a story you may not believe... tentacle and all. It happened in a private cenote called Maravilla, just down the road from Puerto Morelos. My friends Noe and Joanna had just returned from a dive trip to Mahajual on the southern edge of Mexico's Caribbean coast and they brought two divers back to Puerto Morelos with them--two girls, one a Chilean dive master and the other a Canadian dive instructor. Both had extensive scuba experience. The girls were interested in