Largely non-malicious game of obstruction and irritation. When someone is trying to get through a crowded seating area, and the seated people set about obstructing them as annoyingly as possible with their legs. This may not sound particularly harsh or amusing, but is surprisingly difficult to escape if the legs maintain a downward pressure. The combination of "walking through treacle" and "double gravity" can often lend a pleasing edge of panic to the victim's face. Endless repetition, as is so often the case, may result in tears. (cf doccer kill)

The malicious version of sea of legs is the much more macho run the gauntlet, and differed in that the victim volunteers to avoid the legs to demonstrate his skill and agility, and the other participants will trip, spit and kick out viciously, hoping to cause the most serious injuries possible.