Halo: Spartan Assault skulls

Halo: Spartan Assault skulls are game modifiers featured in Halo: Spartan Assault with the appearance of a human skull. Unlike previous Halo titles, Spartan Assault skulls do not increase the player's in-game score. Instead, they multiply the amount of XP the player is awarded upon completing a level.

Black Eye
Energy shields don't recharge unless the player melees enemies. Adds +1.5 to XP multiplier.

Blind
Vital HUD elements are hidden. Adds +1 to XP multiplier.

Famine
All dropped weapons have much less ammo. Adds +0.5 to XP multiplier.

Hollow
The player only has a shield. Adds +2 to XP multiplier.

Pacifist
Shields and armor deplete when firing a weapon. Adds +2 to XP multiplier.

Thunderstorm
Enemies are more challenging. Adds +1 to XP multiplier.