Ignore Line of Sight (sometimes also called Ignore Obstacles) is an attack behavior characterized by ignoring Line of Sight. It is part of the damage types family.
Ignore Line of Sight is represented on the Bloons Wiki as , the upgrade artwork for Arcane Mastery in Bloons TD 6, which was the original upgrade that allowed Wizard Monkey to ignore Line of Sight until Version 3.0 when Guided Magic now does this. Ignore Line of Sight is a separate property and is merged into Lobbing for projectiles that are visually thrown over obstacles.
There are two subsets of this: Flying and Tall . Flying is for airborne attacks, such as Monkey Aces and Heli Pilots. Tall is for attacks that can partially ignore Line of Sight due to a slight height advantage, a prime example being Bloon Exclusion Zone.
Most towers require an upgrade to gain Ignore Line of Sight. Airborne towers such as Monkey Aces and Heli Pilots have this by default as Flying . Alchemists and Spike Factories ignore Line of Sight, but belong under Lobbing instead due to how they attack. Obyn Greenfoot, Ezili, Adora, automatically have Ignore Line of Sight. Etienne's drones automatically have Flying.
There are very few balance changes involving ignorance of Line of Sight. Version 30.0 was the first such case; X-Ray Ultra MK gives Ultravision with Ignore Line of Sight , but Rocket Storm (including M.A.D Rocket Storm) loses said attack behavior. An undocumented line-of-sight change also happened in either 31.0 or 32.0, with Bloon Trap and XXXL Trap gaining Ignore Line of Sight.