P.A.C.M.A.N.

P.A.C.M.A.N. (Pessimistically Aggressive Creature Munching and Noshing) is actually not a blimp, it is an entity lurking in round 256. It is the boss of that round, and it will munch, nibble, and devour your monkeys effortlessly. It does follow the path of the map, but occasionally, it will veer off to eat one of your towers. It has 20,000 HP.

Abilities - Every 10 seconds
Munch - The classic, old method of killing. Veers off the track and eats one of your monkeys. 50% chance.

Gnaw - P.A.C.M.A.N.'s mouth opens up twice as much, and eats two monkeys at once. Happens very rarely. 3% chance.

Beam - P.A.C.M.A.N. shoots out a large, yellow beam that deals 50HP per second. P.A.C.M.A.N. spins around very quickly while doing this. 2% chance.

Power Pellet - P.A.C.M.A.N. eats up your strongest tower, unless its total cost is over $40,000. After this, all of your monkeys become blue and start to run around the map aimlessly, as P.A.C.M.A.N. attempts to catch one of them and eat it. 10% chance.

Pac-Burst - P.A.C.M.A.N. explodes into a yellow burst that deals 10HP damage to each tower. The radius is that of the tower that has the highest range, except infinite range towers, of course. 35% chance.

Trivia

 * It appears at round 256 because in the original arcade version of Pac-man, the stage glitches out weirdly and letters and characters pop up on the screen.