Going back in time to stop Adolf Hitler is one of the most common tropes in science fiction – so much, in fact, that it’s often used as a thought experiment to explain a given work’s rules of time travel. Ever since Donald Trump first gained a lead in the Republican presidential primary, people have been joking that something similar might be needed to stop him. Stephen Colbert took that joke to its fullest extent on Wednesday night, when he recruited Quantum Leap star Scott Bakula for a new time-travel adventure.

Colbert saw a Quantum Leap rerun in which Bakula’s Scott Beckett encountered a young Trump and inspired him to go into real estate (a real episode), so Colbert attempted to reverse-engineer the process. Unfortunately, most of their early efforts were fruitless. Bakula tried to tell young Trump not to go into politics, which only inspired him to do it just to spite his cab driver, according to Colbert’s quantum computer. Telling young Trump that Latino people are nice only inspired young Trump to fall in love with a woman from Mexico, who would then break his heart and inspire the wall. Eventually, things got so desperate that Colbert suggested offing the young Trump (“it’s the middle of the night, no one’s around, you probably got a crowbar in the trunk, and the East River’s right over there”), but Bakula decided to just tell the future Republican nominee to ignore everything he said. This, at least, restored the time-stream to normalcy … except for Bakula’s newfound dog body.