Twinsanity is a Gun Perk in Call of Duty: Infinite Warfare. It allows the HVR and Auger to have akimbo, which allows for a tighter hip spread and devastating damage up close. It is only available to the HVR - Gemini and Auger - Fury variants.
The icon for "Twinsanity" gun perk is near identical to the akimbo icon for Call of Duty: Modern Warfare 2, as the UMP45 and the HVR share a very similar model. In fact, the guns are statistically very similar to each other and could also be another reference to those who used akimbo UMP45.