If you could revive one extinct species, which would it be?

[Silvanus]

Megatherium (giant sloth), or, if we could be sure to protect ourselves from it, the Giant Orthocone.

 

[Do4600]

Oh, what to choose, what to choose, nine foot saber-tooth salmon...no. Giant Polar Bear...no. Nine Meter Manatee?...no. Woolly Rhinoceros?...no. The four metric ton turtle?...maybe. Eight foot long beaver?...sounds pretty awesome.

I think I would revive Protaxites, there were huge 26 foot tall structures made of fungus that existed in the Devonian, if only for some variety in large structured stationary organisms around the planet.

Either that or Terataspis Grandis(Great Monster Shield) a giant Trilobite.

 

[gagagaga]

I'd bring back Quetzalcoatlus, a pterodactyl as tall as a giraffe that could freaking gallop.