The Bucket of Liquid Antimatter is an item that contains Liquid Antimatter, which is a white fluid that gives you horrible effects when touched.
The Liquid Antimatter naturally in the Coralium Infested Swamp biome in caves or in pools underground.
This item needs a lava bucket, a water bucket, a bucket of milk, and a liquid coralium bucket, as well as 5 iron ingots. (recipe removed as of AbyssalCraft 188.8.131.52)
This is used as the ingredient for the Oblivion Deathbomb.