With friends like these, who needs enemies? They say surfers share a special bond of camaraderie and mateship - but not on this boat.
A group of surfer dudes and dudettes videoed while they pushed their friend overboard as a huge shark approached, in a prank that may not have seemed so innocent had it ended differently.
In good news for the victim and his buddies, the beast from the deep was later identified as a basking shark - those gaping jaws are designed to catch nothing bigger than plankton.
Irish surfers certainly seem to have good senses of humour - the victim laughed loudest of all, and seemed to agree with the video's Youtube subtitle, "craic was good".
Basking sharks can grow up to 11 metres long and weigh as much as seven tonnes.
They are distinguished by their propensity to breach clear of the water like whales, with an athleticism that proved handy for this specimen as it was forced to arc out of the path of the surfer and his boat.