RX first appeared in 3 Nights at Freddy's as a side antagonist, however in Five Fearful Nights at RX's, he is now the main antagonist and one of the most active ones.
He acted like BB in 3NaF but in FFNaR, he is the first one to be active and switches room in a fast movement. Although he can be easily warded off by using the light mechanics.
RX's appearance looks simillar to a male sign printed in the rest rooms, sharp tips at his feet and hands. His arms resemble flippers from penguins, his eyes are light cyan with a white light at the center. He seems to be smiling all the time and his main color is White.
NightmareN. RX looks different from his normal form, he seems to be bulkier and his feet is flatted. He has now 3 fingers with sharp endo nails coming out from them. He has a huge rip on his stomach and a rip from his left eye. Both of his eyes are black and has glowing cyan pupils. At his very chest has a glowing red orb that is attached to the endoskeleton.
- RX is also based on Nightmare and The Puppet.
- His current name is "RX", this is a reference to Shadow Bonnie from FNaF World's, though the full name is RWQFSFASXC.