Blastapopoulos: Demon of the Core (formerly Blastopopoulos) is an Event-only MOAB-Class Bloon in Bloons Monkey City.
Its track is a lava field (related to a volcano tile) and moves at the speed of a ZOMG. It works as any other boss fight, except it hurls a fireball at the most expensive tower to stun it for a while, and it keeps doing it. After a while it will target another tower, making the affected tower basically useless. Upon death, it will say "I shall have my revenge!" It made its debut on November 25th, 2015. This boss has been made available to BTD5 Mobile and BTD Battles since May 2016.