S.T.R.O.I.

The S.T.R.O.I. is a giant flying machine which was created by Seabob in order to kill Seabill and steal his identity. Later it was also used to kill members of the beaver family. At the end it destroyed itself from an attack being redirected towards it.

Gameplay
As the final boss of the game, the S.T.R.O.I. is a dangerous enemy. It has several phases, each changing given the current location and health remaining. It's attacks are:

Phase 1

 * Firing a stream of damaging blue stars that move in a straight line.
 * After reaching the stalagmite area, fires a barrage of yellow stars in a wide spread.

Phase 2 (Note that the S.T.R.O.I. is behind Mike in this phase)

 * Fires a circular spread of fireballs from the thruster, which fly forwards, then up.
 * After taking enough damage, fires a stream of blue stars that are aimed less straight and moves far faster than the ones from phase 1.

Phase 3

 * Flies away, and summons all three Chipomats to cover it.

Phase 4

 * Fires a single blue star that travels slowly.
 * Opens a hatch on it's underside that fires several blue stars that travel quickly in a straight line.
 * After taking enough damage, starts shooting additional larger blue stars that explode into a circle of small yellow stars.

Phase 5

 * Goes ahead of Mike, and begins to charge forwards at him, marked by a white dotted line.
 * After taking enough damage in this phase, will start firing more large exploding blue stars, a spread of marine-colored stars.

Phase 6/ The end of the boss fight

 * The Strange Traveler must strike the S.T.R.O.I. in specific areas, marked by an exclamation point. Doing this final phase kills the boss.