Kumail Nanjiani is a big fan of horror films. But as a natural beta male, he can’t quite cope with the feelings of terror they inspire in him and much of his life is spent in a state of fear. When he talks of being unable to visit the toilet during the night after seeing Paranormal Activity (alongside Matthew Crosby, the second comic to mention that film this Fringe), we both recognise and sympathise with the situation.

Two other scary stories are on a different level altogether. When he recalls hearing inexplicable sounds coming from the attic, he is voted by his flatmates to investigate. He spoons layer after layer of increasing hilarity onto the routine’s imagery as he speculates on the consequences of a violent encounter. The fact that the story ends without a punchline makes it only more real and not an excuse for a comedian to massage the truth purely for laughs.

Meanwhile, the tale of the birthday party in Karachi in which a snake and mongoose fight to the death is simply too horrific to be made up and yet once more he paces it so perfectly that the laughs come just as easily as the shocks. He also does a fine line in surrealist observation too, with his analysis of the phrase ‘best thing since sliced bread’ being put to the test.

Although this gifted Pakistani-American comic delivers the odd minor routine such as his Harry Potter bit and the story of trying to get rid of a dubious tape stuck in his VCR (we’re going back some time here), this is as accomplished a stand-up debut as the Fringe will have seen in a very long time. Kumail Nanjiani is a scaredy cat who is set to become comedy’s top dog.

Assembly Roxy, 623 3030, until 27 Aug, 8pm, £11.50–£12.50 (£10–£11).