Reeks were big, four legged dinosaur looking guys who loved charging at people with jetpacks on. They were native to the planet Ylesia. They also did what their names implied, reek...mostly like feces, but a little like hummus.
A Reek was used to try and execute Anakin Skywalker at the Petranaki Arena on Geonosis, but was killed by Jango Fett after damaging his jetpack and ensuring an easy decapitation by Mace Windu. Aw yeah!