It barks like an aardvaark and roars like an ant.

Convergent evolution is well known- but isn't reverse evolution. It's guided evolution- not guided by a Designer, but by the laws of physics. If you live in water, and want to get around fast (like predators often do and their prey often need to do), hydrodynamics will favour the selection of those individuals which approximate better to a good hydrodynamic shape. If you need to grasp things, get a thumb- and if your thumb has already evolved into something else, evolve a wrist bone into something that works like a thumb. If you need to see the shape and colour of things around you, get an eye- optical laws dictate it will be one of a few available models.

Of course, nearly all the examples we tend to quote are based on the same body plan, head in front, tail behind, a leg at each corner. It would be fascinating to see what could have evolved around a different basic template, but despite the huge blossoming of exoplanets (not long ago some astronomers argued that our Solar system could be unique) I can't imagine being able to peep in on one in my lifetime, or for several to come. Sad. But since the laws of physics are the same, we can expect convergence even there.