The Paint Pellet Gun is a UNSC weapon similar to the "paintball" marker pistol of the 21st century. Like its predecessor, it fires small plasticine pellets filled with brightly-colored paint. The paint pellet gun is often used by United Nation Space Command forces as a non-lethal way of training new recruits in basic combat tactics, or as a method of testing new equipment in combat situations without permanently damaging it.
The Paint Pellet Gun was used by CPO Mendez and drill instructors on the SPARTAN-II training program to introduce the Spartan-II trainees to the unpredictability of a front-line combat zone. Pellet guns were used to snipe the Spartans in parade drills or other supposedly "safe activities" to teach them to keep on their toes during all situations. The guns were also used by a unit of ODSTs during a test of the new MJOLNIR Mark VI armor in Songnam, Korea. It is presumed that most testing facilities use marker guns instead of live ammunition, in order to avoid damaging prototype equipment.
The Paint Pellet Gun was probably only used in the SPARTAN-II training regiment when the inductees were young, around 6 to 9 years of age.
- This weapon was included in a special edition ODST  figure for Halo 2 produced by Joyride Studios. The figure was covered in pink paint splatters, presumably from the gun.