Impaling Pike 2014
Weapon, rare, (requires attunement)
When you attack a creature with this magic weapon and roll a 20 on the attack roll, you embed the weapon in the target. If the target is Medium or smaller and is within 5 feet of a wall or other solid object when you hit with this weapon, it is also restrained while the weapon is embedded. At the end of the target's turn while the weapon is embedded in it, the target takes damage equal to the weapon's damage, with no additional modifiers. A creature, including the target, can use its action to make a DC 13 Strength check, removing the weapon from the target on a success. You can remove the embedded weapon from the target by speaking the weapon's command word.
Properties
Reach
This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it.
Two-Handed
This weapon requires two hands when you attack with it.
Source: Vault of Magic (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details