Erratic

Erratic is a projectile behavior characterized as having random projectile deviation. It is part of the damage types family.

Erratic is represented on Bloons Wiki as, the upgrade icon for Rocket Storm in Bloons TD 6, characterized by the randomized serpent-like behavior that the ability rockets produce. Erratic is distinguished from RNG in that its RNG factor can be amended by proper positioning or upgrades that reduce inaccuracy (e.g. Rocket Storm with Focused Firing or Spike Factory's Smart Spikes upgrade that completely takes the RNG factor out of the Spike Factory). Typical examples with Erratic include Spike Factory, Dartling Gunner, Mortar Monkey, Engineer Monkey's Cleansing Foam, and Obyn Greenfoot's Brambles ability (although he adjusts the positioning of them if bloons are within range). Shotgun Spray features Erratic in its spray of angular attacks, and is a separate variant of Spray  for that reason.

Because Erratic can be quite RNG-heavy, some elements of Erratic have been softened or entirely removed for some upgrades, the most notable example being Wall of Fire, which had a notorious history for being dependent on RNG (due to it's cheap price, but high contact damage making it valuable in completing challenges), although like all towers with the Erratic projectile behavior, proper positioning could reduce the RNG of Wall of Fire's blaze attacks. On Version 25.0, Wall of Fire upgrade was changed so that it always targeted the closest to the Wizard Monkey by default and no longer spawned in random locations. Similar happened to Cleansing Foam and Obyn Greenfoot's Wall of Trees, which now default to Close and can be re-targeted anywhere.