During the first phase of the encounter, the Black Knight summons a ghoul. This is usually easily dealt with.
In the second phase of the encounter, the Black Knight summons Army of the Dead, which he can also cause to explode.
Defeat the in 10 minutes while wearing all blue items, before 3 Volcanos erupt, while everyone in the group has at least 1 stack of Spurting Blood and there are no shamans or paladins in the party but before you spend at least 1000 gold in repairs wiping to the Black Knight.This was obviously a reference to the cinema Monty Python and the Holy Grail, as is the The Black Knight in general. However, there was probably no way this achievement could make it past the PTR to live, as noted by an official Blizzard poster.