Kynopos, the Wind of Enigma

Flying, hexproof from odd mana value
Link — The second, fourth and sixth time a
player casts a spell each turn, add {g} or {u}. If
Kynopos shares a color with the last spell cast
this turn, you don't lose this mana as steps and
phases end.
{g}{u}: Draw a card. Spend only mana produced
by Kynopos to activate this ability.