Underground Park enters the battlefield tapped.
: Add or to your mana pool.
Sacrifice Underground Park: Add or to your mana pool.
: Underground Park becomes a 2/2 black and green Rat creature with trample until end of turn. It's still a land.
: Add 
or 
to your mana pool. or to your mana pool.
: Underground Park becomes a 2/2 black and green Rat creature with trample until end of turn. It's still a land.
