Hydra (Genus) [Wikipedia]
Hydra: Stretchy, Speedy, & Probably Immortal - By: Journey to the Microcosmos
The Complicated Sex Lives of Hydra - By: Journey to the Microcosmos
Phylum Cnidaria Part 2: Class Hydrozoa - By: Professor Dave Explains
Hydra catching and eating a Mosquito larva - By: The Micro Universe