Manta, the Behemoth of the Deep was a creature that was shot with an arrow covered in three drops of a black liquid from a vial. The arrow was used in a crossbow to kill Manta, a creature ten times the size and strength of a dragon. It was believed that, like Deathwing, the Manta was unstoppable.Template:Cite
It was said that the black liquid was used to kill this beast 100 years ago which is about 90 years before Warcraft I.Template:Cite
Some speculate that the Manta was somehow linked to the Old Gods, but chances of that are low since four of the five Old Gods were chained beneath Azeroth (Possibly 3 now that C'thun may be dead) and the 5th God was slain with a sword.