Although BADs normally have 55,760 RBE (98,360 when Fortified), the health of all MOAB-Class Bloons increases with each round after round 81, so the actual RBE of the BAD on round 100 is 67,200 (429,920 for Fortified BAD on Round 140). Like all MOAB-class Bloons, BADs have four damage phases.
BADs are the biggest threats throughout deep Freeplay, leading to a lot of strategies revolving around dealing with them.
First Strike can instantly destroy the BAD on round 100 if it has taken around 25,000 damage first (19,500 if Big Bloon Sabotage is enabled).
At the last damage phase, its left and right turbines are destroyed, a simple indicator that the BAD is beginning to be within insta-kill range. With Big Bloon Sabotage, the BAD reaches its final phase once it has taken 20,160 damage; without it, it's 22,400.