Rick's Father (known only as Mr. Sanchez) is the father of Rick Sanchez, the grandfather of Beth Smith and great-grandfather of Summer Smith and Morty Smith. His real name is unknown and he has never been seen in the show. He was mentioned in the episode Auto Erotic Assimilation.
In the episode Auto Erotic Assimilation, Rick and Unity were going to have an extremely kinky sex orgy, which involved multiple different things. One of Rick's requests was so that "Every man that remotely resembles his father would watch."
- Although it is unknown what Mr. Sanchez looks like, after Rick's sex orgy with Unity, involving every man that looks like his father, there was a group of short, middle-aged men that were all wearing white suits, blue ties, glasses, and short hair. This could be a hint toward what Rick's father's appearance and usual clothing attire is.