A Tzarakk can raise up a corpse as a disposable steed with this skill. I don’t know how much utility this skill has. Can it be used to gain a powerfully resistant monster till boot? Can non-tzarakks use it? Does it only work on outerworld monsters?

The in game help reads:

Skill duration: 5.
Type of skill : neutral skill.
Affecting stats: None.
It uses 50 endurance points.
Faithful followers of Tzarakk have been known to employ anything in 
their service - even the corpses of the already dead. While this may 
sound like a powerful capability, there's a drawback - the corpses 
animated by chaos cannot heal on their own, making them more or less 
disposable assets.