I understand why you used " turn into." Anyway, Mareep turns into Flaffy.
trade him
Into Flaaffy at Level 15 and into Ampharos at Level 30.
mareep can't be obtained in leafgreen but can be caught in emerald to trade it you need two wireless adapters and the national dex.
Mareep evolves into Flaffay at sheep Pokemon at level 15.
Normaly you can't, but a use gameshark!!
Mareep is an Electric type pokemon.
Mareep evolves into a Flaaffy, then an Ampharos.
mareep evolves at level 15 then at level 30 in Pokemon crater
You can either catch a mareep, breed a mareep, trade a mareep or go to the global trade station and ask 4 a mareep/ Ampharos :)
with a pokeball
in 4-7 islands
Mareep will evolve at Level 15 in Pokémon Crystal.
Mareep is #179 in the national pokedex, and it is an Electric type Pokemon.
it evolves into ampheros
trade
Nowhere.
yellowish