How to add a hitbox to an object to make it do damage to other player ?

[wise skiff]

Hey everyone !
I'm trying to create a laser gun, like a giant one that shoot à giant laser, so I made the laser and its animation with the maker pen, I'll find later how to actually make an object (like a blaster) shoot the laser when I press the trigger with it in my hand, but for now I just want to know how to add a hitbox, that will grow with the laser animation and that do damage.
I hope I managed to make you all understand what I want to do, thanks in advance for those who will help me !