The pixel spray is one of the spray types available to specific heroes earned via achievements.
Naptime: Interrupt an enemy ultimate with Ana's Sleep Dart.
Triple Threat: Kill 2 enemies in each of Bastion's configurations without dying.
Shot Down: Prevent 1500 damage with a single use of D.Va's Defense Matrix.
Their Own Worst Enemy: Kill 2 enemies with a single use of Genji's Deflection.
Simple Geometry: Get 2 killing blows with a single use of Hanzo's Scatter Arrow.
Mine Like a Steel Trap: Knock an enemy into your Steel Trap using Junkrat's Concussion Mine.
The Floor Is Lava: Get 3 killing blows while wallriding without dying.
Whoa There!: Interrupt an enemy ultimate ability with McCree's Flashbang.
Ice Blocked: Block 1200 damage with a single Ice Wall.
Group Health Plan: Restore 200 health for 5 players without dying.
Halt State: Pull enemies into 1000 damage with a single use of Orisa's Halt!.
Clearing the Area: Knock an enemy to their death using Pharah's Concussive Blast.
Waste Not, Want Not: Get 3 solo kills with a single clip of Reaper's shotguns.
I Am Your Shield: Block 8000 damage using Reinhardt's Barrier Field without dying.
Giving You the Hook: Interrupt an enemy ultimate ability using Roadhog's Hook.
Rocket Man: Get 2 killing blows with a single use of Soldier: 76's Helix Rockets.
Hack the Planet: Hack 15 enemies without dying.
The Car Wash: Hit an enemy with 6 beams simultaneously.
Armor Up!: Have one of Torbjörn's Armor Packs on 5 allies at the same time.
Total Recall: Recover 400 health using Tracer's Recall without dying.
Did That Sting?: Kill 4 enemies using Widowmaker's Venom Mine in a single game.
Mine Sweeper: Destroy 10 turrets or traps using Winston's Tesla Cannon without dying.
Power Overwhelming: Keep Zarya's Particle Cannon above 70 power for 60 seconds.
Rapid Discord: Get 4 kills or assists with Zenyatta's Orb of Discord within 6 seconds.