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You would think there would be a huge difference between a 13-year-old and an 18-year-old. Luckily, when it comes to teenage boys, this isn't necessarily true. Warfare, guns, explosions – they're popular with the whole age range (it's just that the level of violence and bad language increases with the age rating).
Appearance is more important than it used to be (he will, these days, be dragged away from alien destruction for the sake of his social life). But practical jokes are still popular. No teenager is so cool that he won't voluntarily make himself look completely ridiculous if he feels the occasion demands it.
So it's extreme silliness or total war. You choose. Or just buy him an Amazon voucher.