When I think swamp, I not only think alligators, but also mosquitos, like Jumaji sized mosquitos. I sadly don't have time to write out a fully developed dossier so here's the basic concept.
Minimal damage and health, about equal to the current phirahnas or the dragonflies. Attacks and "Syphon" induce minimal amounts of Torpor through the vemon in the Blood Thinning Acid they use to drink easier. Surprisingly intellegent for insects. agression is normall aggressive unless it has recenter fed (neutral after feeding for 30 minutes). Non-Violent Tamable by wearing insect Repellent and hand feeding blood bags made from the Blood Extraction Syringe. Not large enough to be mounted, instead these are loyal pets and sit on your shoulder. Utility would be to extract blood from unconcious creatures/players for personal use. Stops syphoning blood if the victim is below 10% health (both Wild and Tamed). During the syphoning unconcious creatures, torpor is very slightly increased or atleast held steady, also does not affect the Taming Progress. This would be potential early utility to ease the use of narcotics. Blood bags the mosquito syphon are put into its inventory and last 5 times longer then when in the players inventory.