Ether Spear

Alter: This spear can slip through the Ethereal Plane to reach its destination. You gain a +2 bonus to attack and damage rolls made with this weapon, which deals force damage instead of piercing. When you take the Attack action with the spear, you choose a point you can see within 20 feet of you. The tip of the spear vanishes and reappears at that point, allowing you to make melee attacks with the spear against a creature in or adjacent to that space until the end of your turn. You ignore half cover with these attacks and treat three-quarters cover as if it were half cover.

You can use a bonus action to see 60 feet into the Ethereal Plane for 1 minute. Once this property has been used, it can't be used again until the following dawn.

Attunement: Yes
Rarity: Very Rare
Type: Spear
Cost: 13500gp

Griffons Saddlebag, Vol 1

Half Cover
A target with half cover has a +2 bonus to AC and Dexterity saving throws. A target has half cover if an obstacle blocks at least half of its body. The obstacle might be a low wall, a large piece of furniture, a narrow tree trunk, or a creature, whether that creature is an enemy or a friend.

Three-Quarters Cover
A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws. A target has three-quarters cover if about three-quarters of it is covered by an obstacle. The obstacle might be a portcullis, an arrow slit, or a thick tree trunk.

Total Cover
A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.