World's Largest Arthropod

Hail Crabzilla! The Japanese Spider Crab is the biggest arthropod on Earth--their legs are believed to grow up to 12 feet long. But since they live at such great depths (typically 1,000 feet down or so) a full grown spider crab has yet to be caught. So for now, we'll have to make due with the 5 foot long Crabzilla (that's what it's called--I didn't make it up!), one of the largest known crabs in the planet. (Link)