For the targeting option for self-mobile flying units, see Lock in Place.
Locked (or Fixed in BTD5) is a targeting option for the Dartling Gunner in Bloons TD 6 Generation games, and was first introduced for the BTD5 Dartling Gun with Tier 3 Dartling Ammo Dump. It sets the Dartling Gunner to rotate towards the direction of the locked target, similarly to a Mortar Monkey with Set Target. The target can be repositioned anywhere on screen. On mobile versions, the locked target defaults to the center of the screen unless the Dartling had rotated beforehand. On desktop versions, the Dartling always locks onto where the cursor was at the time of setting to Locked, or to the center of the screen if the Dartling never rotated.