Most often, if you are very very lucky and catch a glimpse of a Boomslang, it is green, or green with black markings, or beige. Sometimes boomslangs are even grey or blackish. But once in a blue moon, you might even find a red one.
If you don't agree that finding any snake, ever, should be considered lucky, you should reconsider. Sighting a boomslang is more rare than seeing a leopard or a pangolin. The boomslang is a graceful, stealthy hunter of the heights, climbing trees in search of chameleons and birds.
Though poisonous, boomslangs are shy and non-aggressive (some chameleons and birds might beg to differ). The mosquito is statistically more dangerous than this lovely creature, so take your Malarone and keep your eyes open for a boomslang, and if you're lucky, very very lucky, you might catch a glimpse.