Activate submerge using target option to permanently reveal camo bloons in its radius.
~ Description from BTD 5 iOS
Submerge targeting option permanently reveals Camo Bloons in its radius.
~ BTD6 Description
Submerge and Support is the 3rd upgrade on Path 1 for the Monkey Sub in BTD5 and BTD6. It costs $425 on Easy, $500 on Medium, $540 on Hard and $600 on Impoppable. It adds a new Submerge targeting option. When selected, it stops firing darts, however, it starts removing camo from Bloons in its range, including DDTs (both BMCM and BTD6). The decamo effect has infinite pierce, but only applies every 0.3 seconds.
In BTD5 generation games, the target settings must be changed manually to use the "Submerge" option, though in BTD6 it automatically changes to "Submerge" targeting upon upgrading.
In certain spots on certain maps, Submerge and Support can decamo all bloons throughout the game.
Note that the Bloontonium Reactor can reveal camo bloons more reliably and deal damage to them.
In a pinch, it is possible to unsubmerge the sub to use its main attack.
This is the main use for crosspathing the sub as crosspathing does nothing to the decamo effect.
Constantly changing the targeting option between Submerge and another one seems to make the Sub decamo faster. (?)
Beware of Round 100 if Submerge and Support is your only decamo as the DDTs can spawn in an unfavourable spot for the Sub.
The Submerge and Support is a good option to start of a game of 2 Mega Pops. After setting up your defense, submerge the sub to reveal camo while not stealing pops and unsubmerge to attack when needed.