While a difficult pet to get, as The Twins are still difficult to solo, this pet will be a very powerful combo in any battle against a pet that uses multiple small hits to do a lot of damage. Its sandstorm makes it virtually immune, if not utterly immune, to these effects.
In addition, this makes Anubisath Idol an extremely potent creature against two of the Masters: Courageous Yon, and the Pet Master herself, Aki. One Anubisath Idol ca nbe used to shut both these Masters down almost completely, while giving space to level even a level one pet with the XP gotten off your win. Simply keep Sandstorm up, time Deflect to the big attacks (Dive, Fly, Burrow, and Chew), and you will win 9 times out of 10 without having to use a backup pet.
EDITED: Because Frost Shock now chills the enemy, where it didn't when I first posted this tip.