I just gave it a shot with my 48 hunter;
-Summoned Aquementas
-Pet aggroed him
-Tried a few shots with my gun (missed most)
-I got aggro
-Pet got aggro back
-Pet died
-I got aggro again
-Used Feign Death
-Item made & Aquementas despawned

Either its a bug or the item gets created when the battle ends and without you dying, if thats the case then Feign Death is a nice workarround :)
Pet needs to be dead or dismissed ofcourse otherwise the battle will still go on.

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