Torso of Morpheus carrying a machine gun in his right hand, from the film Matrix
Beware of silent dogs and still waters (Portuguese proverb)
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Beware of silent dogs and still waters

Portuguese proverb

most likely a Portuguese proverb, could even be a Latin proverb, warning us about unusual behaviour and apperances, i.e. there's something strange and unnatural about a dog that doesn't bark, and water that doesn't move stagnates and eventually becomes poisonous
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