Sometimes I have noticed that random, normally harmless creatures, such as Trashgulls, Street Turkeys or even Foxes would spawn as "Hero Variants".
As these creatures are by default already fairly weak, their Hero Variants are rarely... of any threat to anybody, but because they are "heroes" they can, sometimes, carry very powerful objects.
On one hand, somebody could consider this "Good Fortune".
On the other... and I am guilty of this as well, it's sometimes hard to justify killing a random Trashgull or other "harmless" animal, simply because, "It looks more dangerous"... but then you might lose out on a useful piece of gear or object that you could sell or use.
So, my suggestion would be to remove the weaker/harmless animals from the "Hero Rotation".
Kill the Prestigious Trashgull, WriterX.
Feed on its power.
Fulfill your destiny.
And when the truth finally dawned,
It dawns in guano!
But, there is one they fear,
In their tongue he is Gullvahdiin:
BIRDBORN!
This is EfU. Surely the correct solution is to give these things high AB, horrible damage output, and the ability to cause instant, bloody regret to any fool PC who underestimates the local equivalent of the Rabbit of Caerbannog from Monty Python.
"Foul-Tempered Trashgull activates Fear Aura"
"Foul-Tempered Trashgull attacks with Chaos Spittle"