D.H.A.R.K.O.N.

The D.H.A.R.K.O.N. (Dark Horrendous Atrocious Rampaging Killer Of the Night) is another very powerful blimp created by Apopalypse Bloon to destroy the monkeys. It first spawns on Round 315, and every 315 rounds after that. It has 315,000 HP with 2 Auracrysts, and when popped, it spawns 2 K.E.F.K.A.s and 2 G.A.L.E.E.M.s. It looks like a completely black-colored BAD. It moves at the same speed as a G.A.L.E.E.M..

Attacks
Darkness Cover: Turns the screen black for 3 seconds. During this time, towers can't see in the dark, so they can't attack. Cooldown: 30 seconds

Bombs of Darkness: Similar to G.A.L.E.E.M.'s Light Bombs, but the Pineapples are colored black and the explosions emitted are colored black as well. However, the attack does the same amount of damage. Cooldown: 60 seconds

Darkness Impale: Shoots black spikes at your towers and heroes. Deals 40 damage to towers and heroes. Cooldown: 45 seconds

Succumb to the darkness!: Possesses a random number of towers and/or heroes on the map. The maximum number of towers/heroes it can possess is 10. Like G.A.L.E.E.M.'s Light Possessing ability, possessed towers/heroes have red eyes in place of their regular eyes, and will attack your towers instead of the bloons. You can only defeat the possessed towers/heroes by selling them. Cooldown: 45 seconds

Go forth, minions.: Summons 20 random M.O.A.B. Class Bloons. 2 of them will be a K.E.F.K.A. and G.A.L.E.E.M.. Cooldown: 50 seconds

Dark Off-Waves: Emits 3 shockwaves with the range of a 0-0 Super Monkey, damaging towers and heroes caught in them. Each off-wave does 50 damage. Cooldown: 45 seconds

Drown in darkness!: Similar to the Darkness Cover attack, but you get an instant Game Over when the screen goes back to normal. However, this ability is very rarely, if ever, used.

Trivia
Another obvious reference...

The "Drown in darkness!" attack is a reference to Mephiles the Dark's quote of the same name.