Mortyism is first seen in the episode Close Rick-Counters of the Rick Kind, being practiced by the captive Mortys. Morty Smith is given a propaganda comic book called "The Good Morty", a parody of Chick Tracts. Later, he is mistaken for the One True Morty.
The religion is elaborated on in "The Good Morty", a physical version of the fictional comic included in the Season 1 DVD, as well as several other "Mortytracts" which can be unlocked in the Rickstaverse Instagram game.
The core belief of Mortyism is that Mortys must avoid Ricks and their adventures at all costs. Adventures are seen as a form of abuse, and Mortys are encouraged to be self-reliant. Mortys are also taught to protect and love other Mortys.
"…and each Morty should have love for oneself and all other Mortys." - Sacrimortys 4:23
Mortys who are righteous is believed to be rewarded after death in "The Morty Afterlife Zone", where they will live on eternally and receive each a space motorcycle and various versions of Jessica to have sex with.
Mortys who disobey are said to suffer a thousand years of torment, trapped inside the body of a cockroach. The One True Morty is forgiving, and so after this time they will be reborn again as a Morty and given another chance at redemption.
The butthole is taught to be very sacred, and allowing a Rick to experiment on, smuggle items in or otherwise taint the anus is unforgivable by the One True Morty.
The Book of Morty encourages followers of Mortyism not to stress over school or homework, and that those with mediocre grades will inherit the Kingdom of Morty.
Morty: Mortys are inherently pure, but easily corrupted by exposure to Ricks. Mortys should be self-actualized and look out for their fellow Mortys.
Rick: Ricks are seen as horrible parasites who live off of Mortys and make their lives miserable. In "Mortytracts", Ricks are always portrayed as gleefully abusive towards any and all Mortys they come in contact with. Once a Morty becomes too clingy or whiney, they will dispose of them and move on to a new one. Mortys are taught to avoid Ricks at all costs. Associating with Ricks will earn a Morty one thousand years of torture in the afterlife.
The One True Morty: The One True Morty is the saviour of all Mortys. He rewards those who follow his teachings and punishes those who do not. However, his love for Mortys is so great that every Morty is given an unlimited number of chances at redemption when they are reborn after aforementioned torture.
Jessica: In the afterlife, Mortys are rewarded with many horny Jessicas of various hair and skin colors to have sex with. She too is seen as a sacred figure who must be honored. Mortys are instructed to say her name seven times each morning.
Known scriptures from the Book of Morty are Mortilations, Catechism of Morty, Sacrimortys, Beyond the Garage, Mortyronomy, Psalmorty, Mortynetics, and the Old Mortestiment.
"A Morty who chose to walk with Mortys is blessed with eternal joy. A Morty who chose to walk with Ricks is trapped in torment for a thousand years." - Catechism of Morty 1:11
"The tempting portal glows green and angry, like so many Hulks anuses" - Mortylations 2:13
"Remember when there was only one set of footprints? That's when the One True Morty was carrying you in his Super Action Blaster Jet." - Psalmorty 4:19
Practices/Forms of Worship
Mortys are instructed to kiss each of their toes three times every night, whilst pretending each one is "a Morty in need of love." The purpose of this seems to be a reminder of the universal compassion they are supposed to have for their fellow Mortys.
In Mortyism, masturbation is believed to be a form of meditation gifted on to Mortys as a means of keeping Ricks away. If a Rick catches a Morty pleasuring themselves, they will supposedly be too creeped out to bother them for at least a couple of days. However, the Book of Morty limits masturbation to three of four times a day, to avoid injury.
Playing With Toys
Playing with action figures is seen as a way of honoring the One True Morty. Leaving figures in their original packaging is heavily discouraged. Mortys are encouraged to play with toys every day. In addition to action figures; blocks, remote control vehicles, yo-yo's and video games are suggested. Freemium games are forbidden, however. In Mortylations they are reminded to save their games early and often. The religion has heavy emphasis on preserving childhood and possessing a pure heart. This practice would seem to be a way of actualizing this, and preserving packaging may be "too adult" a way of thinking for a truly righteous Morty.
Origins of Mortyism
Whether or not Mortyism exists outside of Evil Morty's lair, is unknown, though the "Mortytracts" seem to suggest it does. The Mortys practicing the religion there were seen to have given up hope of ever escaping, and used the religion as a coping mechanism, believing their suffering would end in death where they would be rewarded. Morty Smith of C-137 tells these Mortys that they are "not defined by [their] relationships to Ricks", and that they need to be self-actualized. This causes him to be mistaken for the One True Morty, as it is what he supposedly taught.
Mortytracts heavily imply that Mortyism is popular with Mortys that are particularly badly abused by their Ricks, and Mortys that are clones or other science experiments.
Mortyism may have been started by or at least propagated by Evil Morty. The portrayal of Ricks, particularly in "The Good Morty" seem to fall in line with his idea that Ricks don't care about Mortys beyond practical functionality. His ultimate plan may have involved setting himself up to be the One True Morty, but this is never confirmed.