The World War Two Mine was an old contact mine so-called because it was required to be touching its target before detonating, limiting the damage to the direct effects of the explosion and usually affecting only the single vessel that triggered them. Many of these type of mines were deposited in the deep waters of the North Atlantic and the South Pacific, suggesting the one in the lagoon was carried in by storms and ocean currents. The mine was caught by Gilligan while fishing and dragged on to shore, but it was activated by his fishing pole sliding over and falling to the ground. The Professor discovered it was ticking and feared that if it exploded that it would set off a series of explosions in the subterreanean gases of the island, devastating it. Unable to disarm it due to its deterioation, the Professor and the Skipper drew straws to tow the mine out to sea. However, Gilligan eavesdropped and tries dragging it out to sea himself, just barely losing it as it drifts out of the lagoon. Unfortunately, the mine soon drifts back in to the lagoon on the tide, exploding just far enough out that it spares the island of any effects.