...How did my shadow master cast hydra?

[Pren]

slvl20 shadow master on a noddie's 99 assassin fooling around in 1.10 final trying to see what a good combination of traps is.

Ran into a gigantic pack of lightning immune skeletons, so I mindblasted a few, dropped a couple of death sentries for the CE, and began spamming fireblast while the shadowmaster tanked. When the pack lay dead, a lone hydra stood for a few more seconds in the corpses before fading away.

I'm not aware of any magical items with chance to cast hydra.

[BEEFMOTRTON]

IIRC there is a magical affix that gives '10% chance to cast level 3 hydra when struck'

You certainly don't see it often though.

[Ruvanal]

"of Hydra Shield", a gethit-skill effect, 10% chance of level 3 effect. This can appear on magic/rare amulets of ilvl 40+; A low frequency of 1 keeps it from appearing very often.

[Pren]

Wow, and to have it show up on a minion. How rare. I vaguely recall the suffix now that it's mentioned. I should have gone through the AS before posting, but GF has made it the most godawfully dialup unfriendly website on the planet. Thanks guys.