The Demons of Selzar are entities that are close to that of demons. They can possess humans and give them telekinetic powers to move objects such as remotes and trash bags. To summon them, it seems you have to put the blood of a virgin rape victim on your face. It is unknown if the Demons of Selzar are a higher up in the Omniverse (i.e. Chin-Chin, Peace^lords) or just that of a generic demon. The process of summoning the Demons of Selzar may trigger psychological, mental, or physical pain, this theory is supported via Frank summoning them, and giving a pained/fearful expression, and screaming in terror. The demons of Selzar seem to be invisible or just transparent because they have made no real appearance as an individual person/humanoid.
They were first showcased in the 100 ACCURATE LIFE HACKS video, where Frank called upon them to do daily chores for him, including taking out the trash and obtaining the TV Remote for Frank when he couldn't. It is plausible that abusing any summonings of the Demons of Selzar may cause misfortune and restricted to using the power. Filthy Frank is a great example, as he is seen only summoning the Demons of Selzar for doing chores and mundane tasks. And the events before and after have been terrible. As Frank's friend, E.T. passes away, been banished to the Rice Fields, and also is lost and stuck, having his channel replaced by an impostor. Pink guy is heavily affiliated with Frank, so he gets the misfortune as well. Pink Guy is nowadays seen fighting or evading an enemy or associate from Chin-Chin. As Frank is only using The Demons of Selzar to do regular things for him. But beware if the power of The Demons of Selzar is misused, you will be banished to the depths of hell for all eternity.