Sorcerer Eternal

Devoid (this card has no colour)
When Sorcerer Eternal enters the battlefield,
Enchant land.
Choose one:
{2}{r}{r}: Enchanted land becomes a 3/3 red token elemental
{3}{b}{b}: enchanted land becomes a 4/4 black token elemental
{5}{g}{g}{g}: Enchanted Land becomes a 6/7 token elemental with Trample