Rosalina

She has a Spin Attack like Mario and Luigi in Super Mario Galaxy, and is an ability she has had before in Super Mario 3D World. This spin is activated by pressing ‘B’ while in midair. She then dives and does a flip toward the ground. You can activate the spin attack to gain a little extra height at any part of your jump just like in SMG, and unlike Waluigi's extra jump, Rosalina can activate this ability even while in a long jump.

This entry made possible by nicemaster12s post on character abilities

Rosalina can also do a "star cancel" or "spin cancel" in which rosalina cancels the animation of a star which allows you to stay in the level to continue to do other stars. Rarely this will crash the game on normal stars and all you have to do to perform it is activate the rosalina spin (B) as you go in to a star. I usually jump from beneath them and press b right away.

~lloyd