I feel we don't talk about this moment in "Mabel's Guide to Color" enough. This is the smile of a very intelligent 12 yo that probably knows exactly how powerful this beam of light is and that this is a very bad idea. This is the same 12 yo that thinks revenge feels awesome, and when he thought someone stole his spaghetti said "this is a dark day" very ominously. This is, once again, the same 12 yo that has dealt with Grunkle Stan's ribbing all summer.
Dipper knew exactly what he was doing here. Look at that grin. Notice he's the only one here, besides Mabel inside, that has sunglasses on.
Grunkle Stan was victimized. The real question is: what did he do to Dipper that made him resort to this. Maybe he found out Stan lied about his spaghetti.
