The Super Soaker is a summertime staple for every kid. But when your dad is a former NASA engineer, the standard version just won't do. Measuring at seven-feet long, Mark Rober created the world's largest super soaker, complete with Guinness certification. However, you won't want to face-off against this water gun in a backyard battel. The super-sized Super soaker fires water at 272 miles per hour, slicing through anything from a hotdog to a watermelon.