Skulls have been a thing since the beginning of the Halo series and make a return in Halo Infinite. Veterans will know what these are, but newcomers to the series may not. Skulls are hidden collectibles that can be turned on to alter gameplay. There are 12 skulls in Halo Infinite and the first is the Boom Skull.
You can find the Boom Skull in the first mission, Warship Gbraakon. It is shortly into the mission where you will come into a room with automated crates that rise into the ceiling. You will see on the right that is jammed. Climb up to this crate and you will find the Boom Skull.
Related: All Halo Infinite Skulls Locations
If you are having trouble spotting this skull, use your AI scanner to highlight its location on your HUD. Once you do this, its silhouette will appear on your screen. Then you just need to navigate your way up to it and collect it.
The Boom Skull will double the blast radius of all explosives while it is active. This is a double-edged sword as it affects both your explosions and the enemies.
For more information on Halo, check out Entire Halo Infinite Campaign mission list and How to beat the Ransom Keep in Halo Infinite on Pro Game Guides.