Surely an hour watching a potty-mouthed purple puppet trying to read from his book would be interminable? You'd certainly think so, yet Randy (scripted, voiced and literally pulled in all kinds of directions by his master, Heath McIvor) manages to pull it out of the bag time after time. The former hard-living Randy now settles down for the night with a herbal tea and a literary novel while all around him there is hedonistic chaos. But it's fine because his now sober mind has turned to higher plains and he has recently completed a fictional debut entitled Walking to Skye.

However, his intention to turn this comedy show into a book event is stymied by his own stage fright and a penchant for tangential storytelling as he gets deep into the true history of Ernest Hemingway, recalls the tormented bloke he tried to buy a bookcase from on Gumtree, and advises us on the fun you can have with a police officer by pretending to be drunk at the wheel.

Most impressive of all is the adlibbing skills which McIvor brings to the table (or, more accurately, underneath the podium) as Randy banters with audience members he can't actually see. There are some odd (as in infrequent but also peculiar) moments when Randy / McIvor goes off on a laugh-empty musing about healthy eating and environmental policy, but in the main, this is a curse-heavy delight.

Underbelly Potterrow, until 29 Aug, 10.05pm, £11.50–£12.50 (£10–£11).