Vidmaster Challenge B
From Halopedia, the Halo wiki
Vidmaster Challenge B is an achievement in Halo: Spartan Strike. It is unlocked by completing Operation B, Mission 6 with the Hollow and Pacifist skulls active. The achievement is worth 10 Gamerscore. It is represented by a circle with "B-6" and the Hollow and Pacifist skulls inside it.
The Pacifist skull depletes the player's shield with every shot, while the Hollow skull means that the player only has a shield and no health. This means that if the player's shield is depleted, they will be killed instantly. Obviously, this combination severely limits the player's offensive capability. As such, it is highly advisable to purchase an offensive armor ability such as airstrike or seeker drone, and the shield or damage booster.