Boss channelled laser

I’m wanting to create a boss and have one of it’s attacks by a sort of channelled laser where it will shoot a continues laser at one point and slowly move that laser across the floor and up. The only problem is I don’t really have an idea on how to script it, as the laser would have to get longer the further it gets away and then at a certain point, the laser would have to start moving upwards.

Does anyone have an idea on how I could do this?

Have you looked at Raycast?