Hydralisk Dens of Nemesis Brood provides additional protections from a melee aggressors specifically, by making Nemesis Brood's carapace grow with sharp spikes that works like iron barbs.

Since Niadra was often in rush, much to her personal dislikes, she not only made an especially fearsome Zerg Brood, but she also built certain structures with multiple functions. Best example is her Defiler Mound that partly works like Zerg Extractor.

(Zerg belongs to Blizzard)