First of all, these DO NOT summon. I've been there for 3 months killing these
things doing the AA Grind, and never have they summoned. If you pull one
standing near one of the Keepers of the Spires, he will agro too and they DO
summon.
Second of all, in regards to who said these do not drop the augs, that person
is trying to pull your leg, possibly to keep you away from them. All night long
we are constantly "ooc'ing" a "rotting" message, because they drop so often from
these guys.
By the way, a little tip....you can pull a drake standing right beside a bas,
and the bas won't agro. The snakes and basiliks (and Keepers) are not social,
but the drakes will agro within range and a snake will come with him if it's
around.

Amber
Basilisk Egg
Basilisk Meat
Basilisk Scale
Basilisk Skin
Black Sapphire
Bloodstone
Blue Diamond
Elaborate Defiant Leather Tunic
Elaborate Defiant Plate Gauntlets
Elaborate Defiant Plate Helm
Emerald
Jade
Malachite
Peridot
Petrified Bladefin Eye
Serpent Spine Geode
Taaffeite
Versluierd Fungus