In the review of Dragon's Lair for NES and Super NES, Fred asks for the password for the next level to Seb after the former failed to get through a tough obstacle in a level, the latter declines, stating it's too early, Fred asks for the password again, but this time he says it with a satanic deep voice, complete with a Nightmare Face, Fireball Eyeballs, and the screen going darker. Seb subsequently abides with a small "ok".
The ending of the The Legend Of Zelda C Di Games review. Because of a bug in the console, all of Fred's saved games are gone. We are then treated to a parody of the infamous cutscenes... in the form of Seb and Fred through creepy filtered footage that makes them jittery, grainy and bordering on downright Uncanny Valley.
Though there is some Nightmare Retardant a bit later when the victim is shown to have had his fingers replaced with sausages that he can't stop himself from eating because they're delicious.
Episode 4 of the Stranded Deep narrative let's play suddenly takes a terrifying turn when Fred comes across a Megalodon, which upends his boat in the middle of the sea while night is falling. He was lucky enough that the shark had just eaten a whale and wasn't hungry.
In the finale of the Frostpunk LP, the central generator fails and the only way to fix it (and avoid losing the city to a massive storm) is to send a child inside to her certain death, to Seb's cheerful indifference. The girl's father executes Seb after the storm passes.