We can give 'em Improved Disarm as a bonus feat, if you'd like. It is thematically appropriate, after all.
I'm not sure Stealthy is needed, with their Camouflage ability.
Two mobile tendrils are possessed for each hit die that it has. These tendrils can reach out up to 5’ away and can lift up to 5 gp in weight per vine.
It looks like another one for the special Advancement underbar. It also looks like I need to change the full attack line to include a second tendril.
Tendrils can dig into pouches, backpacks, and the like to find items, and more than one tendril can help steal an item. Lifting an item from a victim takes 1 round per attempt.
Should we give it a circumstance bonus if it commits more than one tendril to a theft?
If the plant is successful in stealing a random item from someone, it will hide the item amongst the gnarled vines of the main plant.
From the Sleight of Hand skill description:
You can hide a small object (including a light weapon or an easily concealed ranged weapon, such as a dart, sling, or hand crossbow) on your body. Your Sleight of Hand check is opposed by the Spot check of anyone observing you or the Search check of anyone frisking you. In the latter case, the searcher gains a +4 bonus on the Search check, since it’s generally easier to find such an object than to hide it. A dagger is easier to hide than most light weapons, and grants you a +2 bonus on your Sleight of Hand check to conceal it. An extraordinarily small object, such as a coin, shuriken, or ring, grants you a +4 bonus on your Sleight of Hand check to conceal it, and heavy or baggy clothing (such as a cloak) grants you a +2 bonus on the check.
A pilfer vine will attack only if attacked first. It can lash out with its whiplike vines, doing 1-4 hp of damage per strike and gaining one attack for each mobile tendril it possesses. Up to six vines may attack a man-sized creature at a time. A vine can take 5 hp damage from edged weapons before it is severed and becomes useless.
Since its Str is low and grapple modifier sucks, perhaps a similar circumstance bonus on grapple checks as I suggested above? Something like the mind flayer?
If a mind flayer begins its turn with at least one tentacle attached, it can try to attach its remaining tentacles with a single grapple check. The opponent can escape with a single successful grapple check or Escape Artist check, but the mind flayer gets a +2 circumstance bonus for every tentacle that was attached at the beginning of the opponent's turn.
A pilfer vine takes normal damage from electricity, but cold only does half damage and slows the plant’s movements by 50% for 2-5 rounds.
Shall we include the slowed by cold bit?