When the British Secret Intelligence Service discovered that semen made a good invisible ink, Sir Mansfield George Smith-Cumming noted of his agents that "Every man (is) his own stylo".
nominative determinism on the wikipedia page for semen

howdy i'm not that good at bios! i'm a 23yo artist and nerd from brazil who uses ^_^ a lot
When the British Secret Intelligence Service discovered that semen made a good invisible ink, Sir Mansfield George Smith-Cumming noted of his agents that "Every man (is) his own stylo".
nominative determinism on the wikipedia page for semen
this is one of the times where I think I was too harsh when complaining jack kirby named the character black bolt as Blackagar Boltagon