The Reetou, also spelled Re'tu, are a mostly peaceful insect-like species from Reetalia who are phased 180 degrees outside of the human range, rendering them completely invisible to the un-aided eye and mostly immune to projectile weapons in our phase. They are however vulnerable to Transphase Eradication Rods and multiphasic blasters.
When the Goa'uld discovered them, they feared the potential threat that an invisible species could pose. They devastated Reetalia, killing most of the Reetou, but a number survived. After the attack, the Reetou split into two camps: those loyal to the Reetou Central Authority, who believed that they should fight the Goa'uld in force, and the Reetou Rebels, those who believed that the Goa'uld should be battled with "attrition"—wiping out all potential hosts. (SG1: "Show and Tell")
Even though Jacob Carter said that they will not give up trying to wipe out potential Goa'uld hosts, they have not been seen or heard from again.
Methods of detectionEdit
A Transphase Eradication Rod is capable of making Reetou visible, although it can only do so within a narrow radius in front of it.
Multiphasic blasters, used by the Reetou themselves, fire visible shots which can at least partially expose the shooter's position.
A Reetou will agitate any Goa'uld symbiotes in its near vicinity, causing pain and discomfort to Goa'uld, Tok'ra, and Jaffa. This can alert these species to the presence of a Reetou, although they are still not visible to them.