Corpse Explosion

Corpse Explosion is a death knight ability that allows the death knight to cause a corpse to explode damaging all enemies within 20yds. Corpse Explosion may be cast on a death knight's own (living) ghoul.

Exploded corpses change to meat or bones models and can still be looted and skinned.

Casting on one's own ghoul
As mentioned above, this spell can be used against a death knight's raised ghoul. Though the tooltip does not indicate this, the ghoul's explosion is far different from the effect of the regular spell. Rather than an instant detonation of a corpse for minor area damage, the ghoul's explosion is delayed by two seconds.

The ghoul is lost upon detonation but the amount of damage is significantly more than what is listed in the tooltip. The effect is similar (or possibly equivalent) to the self-destruction Explode ability a player gains when risen by a Death Knight using Raise Dead (pre-3.0.8), Raise Ally (post-3.0.7) or becoming a Risen Ghoul himself.

In order to specify the ghoul as the target of the spell, the ghoul must be selected before the spell is used. This is especially true during circumstances where a compatible corpse is already within range of your enemy target.

In one single test where no critical hits occurred, 155 damage was done by the normal spell compared to around 1500 for the ghoul's explosion. This test was performed before the increase in damage introduced by patch 3.0.8.