how do custom powerup scripts run?

[Shadowblitz16]

I was just wondering how custom powerup scripts run.

I downloaded a boomerang power up but I don't see anywhere in the editor where this script is called.

[Spectra]

Right click the boomerang flower

Now go to behaviors and click script

Insert the script

Do the same with the boomerang [If it needs a script]

and vwala! it should work