Aphix Invasive
The Aphix Invasive is a Vex programming type. Little is known about it as units of this type are very rarely encountered. Aphix Invasive units include the Fanatics and Supplicants found in the Vault of Glass, and some Axis Minotaurs that appear in Public Events, as well as one that appears in The Nexus that spawns in the caves above the final room. They also appear in the Prison of Elders. Aphix Invasive Vex can be identified by their red frames and spikes coming off of their heads.
The Invasive's presence in the Vault of Glass and alongside the Vex Gate Lord Qodron suggest they are a sort of security force, defending high level Vex leaders and structures that would normally be left to the Hezen Protective. This however is all speculation.