I think the "looks like a solid object" --> stable geometry + opacity, which to me means that the laser plasma system produces a consistent effect in the same way you get a red spot with standard laser pointer, though it's a second order incandescence with plasma so it's more volumetric like.

The specific "tic tac" appearance may just be what the effect ends up looking like - see the picture in this article for a tic tac-looking laser plasma ball: https://www.slashgear.com/super-powerful-laser-creates-plasm...