OK, i haven't read all the responses thoroughly, but i plan to on Monday when i return to work and have a chance to print the thread out.
first of all, Conaill suggested a chance to have the link visible using see invisibility and true seeing. do we want to use that or not?
i took what shade wrote several posts back and included some other ideas that i had about how this creature should work. i'm perfectly willing to rework any or maybe even all of the mechanics depending on what we decide to go with.
"Vampiric Link" (Su): A vampire moss can drain the life from any creature within 30 feet. To do so, it must be aware of the creature and take a standard action to attempt to establish a link. The vampire moss doesn't need to touch the creature to establish the link. The target creature must make a DC X Fortitude save.
On a successful save, the link fails to establish, though the vampire moss may attempt again on its next turn. A failed save indicates that a supernatural link has been established. The victim will not be automatically aware of the link, but must succeed on a DC X Will save to notice the attack. Each round of blood drain entitles the creature to another Will save to notice the link, with a cumulative +2 bonus on the check per round after the first.
If its victim dies before the moss's appetite has been sated, the moss seeks a new target. If the victim moves more than 30 feet away from the feeding moss, or if the feeding moss is slain, the link is severed. The save DCs are Constitution-based.
"Blood Stealing" (Ex): A vampire moss can cause persistent blood loss in a creature it has established a vampiric link with. Such a creature loses 1 hit point each round. This continuing hit point loss cannot be stopped by a Heal check, cure spell, or heal spell, though these methods can restore lost hit points. The vampire moss gains temporary hit points equal to the number of hit points lost in this way (which disappear after X days?). If the vampiric link is severed, the blood loss ceases immediately.
Once a victim (loses one-half its normal maximum hit point total to the vampire moss), it must succeed on a DC X Fortitude save or fall unconscious.
After a vampire moss has drained a number of hit points equal to 4 times its own maximum hit point total (X points for a typical vampire moss), it is sated and severs the vampiric link.
also, as for the regeneration: "The only ways to kill vampire moss are by ripping it into tiny shreds or by burning it. The moss regenerates all other damage at a rate of 2 hp per week."
what, if anything, could we do with the whole "ripping it into tiny shreds" part? maybe a coup de grace?