The Black Lake

The Black Lake comes into play tapped.
{t}Add {u} to your mana pool
{1}{u}: The Black Lake becomes a 1/1 Grindylow
with vigilance. It still acts as a land.
"He could only see ten feet around him, so
that as he sped through the water new scenes
seemed to loom suddenly out of the oncoming
darkness: forests of rippling, tangled black weed,
wide plains of mud littered with dull, glimmering
stones." -Harry Potter in the Great Lake