Undead Bloon

Undead Bloons, also referred as Unpopped Bloons or Zombie Bloons, are reanimated variants of Bloons that spawn from Necromancers and Prince of Darkness.

According to Ninja Kiwi, they are not considered bloons technically speaking, but rather as projectiles that resemble bloons. Hence why they are not affected by Big Bloon Option or Small Bloon Option.

Summoning
Each popped bloon nearby the "undeadness" range of Necromancers and Princes of Darkness will become placed in the graveyard of whichever Necromancer (or its upgrade Prince of Darkness) obtains the popped bloon first. Normally, the Necromancer who is closest to the unpopped bloon will obtain that pop first. Afterwards, that bloon becomes transformed into graveyard units. Graveyard units are normally increased by +1 per popped bloon, but Super Ceramics are converted into between 7-13 graveyard units (reduced to 7-10 for Prince of Darkness) to make up for the loss in offspring bloons.

Necromancers will use up a specific amount of graveyard units to produce between 1-4 Undead Bloons using up between 1 to 10 graveyard units. Pierce amounts for the Undead Bloons are based on how much graveyard space was used up, between +1 to +10 pierce on top of 1 pierce. Attack speed of the Undead Bloons is increased (and therefore summons Undead Bloons faster) by +11% (0.90x attack cooldown) for every 100 graveyard units stockpiled, up to 5 times at 500+ graveyard units. Damage of the Undead Bloons increases by +1 every 300 graveyard units, up to 10 times at 3000 graveyard units, on top of the base 2 damage of each Undead Bloon or Undead MOAB (but strangely not for an Undead BFB).

Undead MOABs and Undead BFBs work differently from normal Undead Bloons, and are spawned independently from them. If graveyard capacity is lower than 2000, Undead MOABs spawn. If graveyard capacity reaches 2000 or above, Undead BFBs spawn. Undead MOABs consume a constant 20 graveyard units, while Undead BFBs consume a constant 50 graveyard units.

Graveyard units do not last forever, and only last for 2 rounds, or 3 for all Princes of Darkness.

Behavior
These bloons are spawned in track closest to exit in parent Necromancers range travelling in opposite direction towards normal bloons damaging them on contact, these bloons disappear after 10 seconds have passed. This duration is extended by Prince of Darkness buff, increasing by +50% for a total of 15 seconds duration. Undead Bloons move at the speed of a Red Bloon.

Undead MOABs & BFBs are much stronger variant of regular bloons summoned only by Prince of Darkness, which have stronger damage and higher pierce but move more slowly. Undead MOABs have 20 pierce, deal 40 damage, and last for 20 seconds. Undead BFBs have 50 pierce, deal 100 damage, and last for 13.3s.

Undead Bloons and Undead MOABs can be buffed by Ezili as well as Prince of Darkness.