Barrel of monkeys is awarded randomly while skilling or as a drop from Clawdia during the Summer Beach Party at stacks of 5.
It can be dropped on a surface (excluding bank areas) in RuneScape, releasing a number of grey, scampering monkeys (up to 10, and each monkey lasts roughly 30 seconds before disappearing) which move about randomly. It can only be used once, as the barrel will disappear with the monkeys after use. You can only place 1 barrel at a time. No warning message is given before it is used.
While functionally identical to the Squeal of Fortune version, this is tradeable.