Mobchain (Boss)

Mobchain
First appears in level	4.8 (Wave 50)

Mobchain is the fourth boss appearing in the main campaign. It shows some resemblance to a train. Just like Stakey, it consists of the main head part and a chain of identical body parts, but does not have a tail part. It is immune to any kind of crowd control. Mobchain moves at a speed of 0.8 t/s, making it the fastest boss by default (Stakey with missing body parts can move faster).

Fighting Mobchain consists of 2 phases.

In the first phase, Mobchain's head is completely immune to all damage and cannot be targeted by any towers. Each of its body parts initially takes full damage from all towers. When a body part's health drops below 66%, it gains 90% damage resistance against bullets and explosions. When its health drops below 33%, it gains 90% damage resistance against everything but bullets and explosions.

The second phase begins once all of Mobchain's body parts have been destroyed. The head then becomes vulnerable to damage and targetable by towers. A new set of 'ghost' body parts is spawned, each with a color and an icon above, representing the tower it is most vulnerable to. If these parts are not destroyed, the head will "consume" them to regain health.

The head deals 100 damage to the base, while each body part in the first phase deals 5. Colored body parts in the second phase do not deal any damage, since they disappear once the head reaches the base.

Unlike Stakey, if Mobchain is split into two parts, the back half of the boss will speed up to reconnect with the front half.

Strategy

Defeating Mobchain requires the player to build different types of towers. Freezing and Blast towers do not work against it, so they should be avoided. Burning through the first 1/3 of Mobchain's health is quite easy. The second 33%, however, may prove difficult if the player relies solely on early stage towers, such as Cannon or Sniper. Tesla is incredibly effective against Mobchain, as it can usually damage all of its parts at once and deals full damage until the boss' health reaches 33%. Minigun, thanks to its high damage output, can also be used to quickly eliminate the body parts one by one, even despite the damage reduction. Like other bosses, it takes 90% less damage from abilities. Ball lightning's damage is further reduced by another 90%, resulting in a pathetic 1% of its normal damage output.

Blizzard and Windstorm have no effect on Mobchain.

Trivia

• Mobchain's second phase's segments are internally referred to as MOBCHAIN_BOSS_CREEP.

Bugs

• Prior to version 1.8.0, Mobchain's first phase could be skipped by killing the first segment of its body as soon as it came out of the portal. This prevented the rest of its body from spawning and made the boss go straight into second phase.