The Swamp People have learned to tame the Giant Toads that live there, and their powerful Shamans can even ride them. If the Swamp People are still unknown from the rest of the world, it's probably because most intruders are quickly swallowed by those beasts...
Note that the special effects will not appear in Magos, you have to import the model in game to see them.
The model is meant to use the "spirit of vengeance" projectile.
Edit: I added the Toad without rider, thanks to Kyrbi0 for beginning the job.