Tails is Sonic's best friend, and he has been for an incredibly long time now. He is a two-tailed fox with the power to fly. He propels himself up in the air using his tails. He is a great mechanic who builds airplanes and such. He has built airplanes and robots for himself, which have been seen in many games. He needs a Chaos Emerald to power some of these machines, so he goes off with his friend Sonic to find the Chaos Emeralds. Tails' most popular machine is his trusty robot walker, the Tornado, which has changed its color scheme over the course of Sonic Adventure to Sonic Adventure 2 with its older colors red and white to blue and yellow. In Sonic Adventure 2 Tails has the power to not only fly, but to hover, transform, and to run at good speeds.