Mishra's Laboratory

{t}: Create two colorless 1/1 Venture creature
tokens with "Sacrifice three Ventures: create a
copy of target land".
{1}: Sacrifice a Venture: Put a flying counter on
target land.
{3}{t}: Until end of turn lands you control are creatures with base power and toughness 2/2 and
"{g}: Regenerate". They are still lands.