Natu'mani, Element Sculpter

Primal {1}{u}{r}{g} ( You may cast this spell for its primal cost. You may only spend mana produced by basic lands to do so.)
When Natu'mani enters the battlefield, if you payed it's primal cost, each land tapped to cast it become 2/1 elementals with haste in addition with their other types. They are still lands.
As long as you control 5 or more elementals, elementals you control cost {2} less.