I would like to know how to delete individual items such as rocks, platforms and any item, I would like to remove and replace with something else. Any help is appreciated.

i have... a lot of stuff that i have no idea how to do... but the main ones are:

Something Like an attack based on Lucky charm from Ladybug (do i just make a beam o light with asorted objects falling in the oponent that is inside it?!)

or Shelter (a ultimate that creates an invulnerability shield that can't be attacked for some seconds and that damages the oponents who touches it. similar to a Charged Rolling shield from Megaman X)