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.
this guy gave about 7-8 % aa xp ( 100 % aa ) to me when i was soloing with my lv 75 shaman at the ZI to Goru'kar Mesa. the mob quaded for max 900 hp unslowed ( AC 1800, Avoidance and Mitigation complete set in Archtyp-AA ), it stuns but didn't malo or something. the mob has around 35 kHP. you can malo, slow, snare and root them w/o any problem, it didn't resist dot's around lv 70's. I root/dot the mob to death, it took me around 7k mana per mob. i didn't saw any faction-message after killing the mob, it seems not to be kos.
same on the dragons, that stood together with basilisks and snakes in the near. good to get some aa's here!