I am sure this thread will break many hearts but oh well...
Kanto : Jynx ( Man so horrible and scary...)
Johto : Quagsire ( Hey what's up with that Body...)
Hoenn : Swalot ( Yet again another Slimy fellow with 0 level of being famous)
Sinnoh : Burmy family ( I just don't like them except Mothim)
Unova : Yamask ( What is this thing !!!!)