There is hardly any millennial who did not own a laser pointer as a kid. Well, those lasers didn’t do much more than pointing at things or making shapes with some stencils. You can wave your laser pointer to make some trails, but you can not make much of a perceptible image out of it. A cheap 3D printed plastic gadget can turn your simple laser into a lovely little light show.
You can print the gizmo for yourself using the files available at Thingiverse. It includes a series of irregular cams that spin, moving the laser pointer in specific patterns, making stars, the Batman logo, and you can even choose to make your own pattern by printing a custom 3D disk with your printer. You will need good math skills to be able to do that though.