Harpoon, Variant (3.5e Equipment)
From D&D Wiki
Can also be used as a one-handed weapon while being used by a mounted character, or when being thrown.
The harpoon is a broad-bladed spear forged with barbs. The shaft of the harpoon has a trailing rope attached, to control harpooned opponents. Though designed for hunting whales and other large sea creatures, the harpoon can be used on dry land. If it ideals damage, the harpoon lodges in an opponent who fails a Reflex saving throw (DC 10 + the damage dealt.) A harpooned creature moves at only half speed and cannot charge or run. If you control the trailing rope by succeeding an opposed Strength check while holds it, the harpooned creature can move only within the limits that the rope allows (trailing rope is 30 feet long). If the harpooned creature attempts to cast a spell, it must succeed on a DC 15 Concentration check or lose the spell. The harpooned creature can pull the harpoon from its wound if it has two free hands and takes a full-round action to do so, but it deals damage to itself equal to the damage dealt. A character who succeeds on a DC 15 Heal check can remove a harpoon without further damage.