WARNING: When facing these creatures, it is vital to kill/disable them before they can hit you. With the exclusion of Evolution, who can restore herself by transforming, this creature's default attack will PERMANENTLY lower the target's health, with no way of regaining the lost stats.
Your first impression might be that of a simply more dangerous Stinger, but there's more to this flying glass cannon. The max hp they drain from enemies can be sacrificed for increased Strength. There's an increasing cost so it's not infinite, but with the right traits added on top they can hit surprisingly hard. Even after you find a better unit for your party, the LifeBlood they produce is valuable enough to keep one around.
They can be sold for 100 gold at Medium size and for 300 gold at Enormous size. Every level above 1 additionally increases their price by 5%.