To reiterate what I said very recently, I imagine the krown toss would be similar to Snake's Nikita missile: K. Rool yanks the krown off of his scaly noggin and hurls it with tremendous force, at which point it can be aimed at will and will remain in duration for a set amount of time, until it encounters a tangible entity such as an opponent's hurtbox, a wall, the floor or a platform or until K. Rool himself is hit. Either way, when its journey is concluded, it immediately snaps right back to K. Rool in a straightforward trajectory, wherein it will damage any opponent it happens to connect with on the way. I imagine another input of the move would cancel it instantly and have it immediately return to K. Rool. This could be useful for surprise setups or to keep away opponents that manage to get past the krown's initial trajectory and try to go ham on K. Rool himself.
The difference between the krown toss and kannonballs is that the krown toss can be directly aimed and is a much slower yet more deadly (due to its greater damage output) projectile, whereas the kannonball is a reusable projectile / item that can be picked up and thrown at will, similar to R.O.B.'s gyro, or it can be charged to release a fast-traveling projectile that does immense knockback, kinda like Jr's own cannonball or Samus's Charge Shot. The ability to switch between these fundamentally distinctive weapons and make best use of their respective properties would make K. Rool a versatile and tactical opponent, and most importantly, it'd ensure he's got a tool to suit various different occasions~