Mortimer "Morty" Smith was a genius-version of Morty Smith from a dimension where Mortys are smart and Ricks are dumb. He was murdered in his garage by Rick.
Morty was a genius teenager living at home with his alcoholic idiot grandfather Rick, who he would constantly make fun of for being less intelligent. He was smart enough to be a part of the Council of Mortys, who he was on good terms with. One day he woke his Rick up from a dream where their level of intelligence were switched. Morty mocked this idea before telling him to join him in the garage, and complaining about how slow he was once he got there. He told Rick to hand him a screwdriver before continuing to mock the idea of a brilliant scientist Rick, which led Rick to kill Morty with repeated blows to the back of his head with a hammer. This murder was witnessed by Rick and Morty from Dimension C-132.
Morty was a very arrogant boy who would constantly demean and make fun of his Rick for his low intelligence. Though he would ask Rick to assist him in the garage, it would usually be to hand him a screwdriver. He found the idea of Rick being brilliant scientist so ridiculous that he was going to tell the Council of Mortys about it, before he died.