The Metal Tiger is one of the 5 different types of Tiger in Chinese astrology. They are exciting, spontaneous, adventurous and unfathomable.
They are also notoriously impetuous, they just decide they're going to do something and then they simply set about doing it - no real planning or forethought whatsoever, just a blindly single-minded mindset.
When it comes off, they're hailed a genius and when it doesn't they're full of remorse and regret. The Metal Tiger never switches off, ever. It's a mind that kicks in at birth and just keeps relentlessly chugging away. This is often not a bad thing really. You'll never be bored around these characters, they regard sitting still for more than three seconds as some sort of personal torture.
Other types of Tiger in the Chinese zodiac:
Water Tiger
Wood Tiger
Fire Tiger
Earth Tiger