Monstar

Monstar was a ghost-like monster that attacked those entering Starborn Valley in Paper Mario. When Mario and his friends first encountered it, Monstar looked like a tough boss. However, Monstar was really nothing more than a bunch of Star Kids trying to protect their home. When Monstar was about to attack, it would make a huge light show with amazing special effects. However, the attack deals only 1 damage point. After attacking, it asks Mario if he is scared yet in a shaky voice.

The battle was really simply moving the plot along than anything else, but Monstar still gives some Star Points.

Also notable about the battle is the fact that Monstar was invulnerable to Star Spirit attacks and the Shooting Star item.

Trivia

 * Its name is a pun on monster and a portmanteau of "monster" and "star".