In Pokemon, if you get a Growithe and put it in G.T.S(Global trade station)  for a Zygarde, you can get a Zygarde for free!  You must wait 3-6 hours though.   Sometimes it doesn’t even have an original trainer! This is a very interesting glitch.  Some people say that it isn’t a glitch and people really want Growlithes, but I put a level 1 Growlithe in and still got a level 80 Zygarde with Pokerus.