Boomerang Pokemon? Ha! No it's never happened to me but if it did without me knowing it was possible it would've really creeped me out!
If a Pokemon has a high friendship rating with you, it will come back every time you attempt to release it.
oh kool...
BTW if u release an UT pokemon e.g. Mespirit u could find it again but the chances of that is lower than finding a shiny!
If a Pokemon has a high friendship rating with you, it will come back every time you attempt to release it.
OK...
so pokemon will always stay of HM's or a Friendship Bond.
still looking for more stories people.