Toxic Rick

Toxic Rick is an antagonist in the adult animated science fiction sitcom Rick and Morty. He is the main antagonist in season three episode six called "Rest and Ricklaxation". Toxic Rick is the physical embodiment of all the negative qualities of Rick Sanchez. He is portrayed by Justin Roiland.

Background
Toxic Rick was created after he was separated from Rick after Rick, along with Morty, using an alien spa that literally removes all toxicity from the users. He and Morty are then sent into a toxic wasteland within the spa tank where visibly unpleasant creatures lived there. At first, both Toxic Rick and Toxic Morty believe the machine destroyed the rest of the spa. However, they soon figure out that they aren't Rick and Morty, but are the toxicity of Rick and Morty. Toxic Rick then plans on escaping the tank. Although he is successful, he would eventually be defeated and remerged with Rick.

Rest and Ricklaxation
Toxic Rick is able to contact Rick by sending threatening signals to Rick's phone letting him know that he's in the machine. He tricks Rick and Morty into letting him and Toxic Morty out of the machine (which is in Beth's house after Rick stole it and brought it with him). Toxic Rick then fights Rick which causes mass damage throughout the house. During the end of the fight, he tries to force Rick into getting in the tank but changes his mind, instead planning on turning the whole world toxic. He attempts to do this by using a Moon Tower to spread toxins over the Earth and convert everyone into toxic versions of themselves.

At first Rick refuses to stop them, saying it's not his place to decide which dimensions are saved or destroyed, but upon getting slapped by Morty, he realizes that the detox machine removes toxicity in a user based on that person's definition of toxicity. Toxic Rick manages to succeed in turning the world toxic just as Rick and Morty arrived. Rick realized that his normal self considered his irrational attachments to people toxic, thus he knows Toxic Rick cares too much about Morty to allow him to die: with this knowledge, he shoots Toxic Morty with a virus that will destroy him, cutting that time in half with each progressive shot until an agonized Toxic Rick finally agrees and remerges with him, and in a sense, destroying him. Toxic Morty would also remerge with Morty near the end of the episode.

Personality
Toxic Rick is the toxic part of Rick Sanchez. Because of this, he is a double-crossing, arrogant, ruthless, maniacal, intelligent, and cunning individual. Since Toxic Rick is a part of Rick, he also has the knowledge to create advanced technology and uses this to his advantage in the episode.