In resort area, if you use surf or super rod , you can get a Pokemon from lvl 1 to 100 which is magikarp. So I was thinking that catching a level 99 magikarp and using a rare candy on it gets a lvl 100 gyarados. Is it possible and which Pokemon too can do that?
well it depends, you cant exit the evolutions which stops them from evolving, lol obvi... and I'm not sure if it continues to evolve when it levels up but you should be able too as far as I know lol xD
hope my useless info helped XDDD
Yes, using a Rare Candy on a Lv. 99 Magikarp will make it evolve. But as a side note, if you like to EV-train your Pokemon, do it before you get it to lv. 100 because in Gen IV games, you must level up to get the effects of EV training.