CardName: Unfathomable Chasm
Cost:
Type: Land
Pow/Tgh: /
Rules Text: Unfathomable Chasm enters the battlefield tapped.
{T}: Add {U} to your mana pool.
{T}: Exile target Kraken, Leviathan, Octopus, or Serpent you
control. Return it to the battlefield at the beginning of
the next end step.
Flavour Text:
Set/Rarity: Multiverse Design Challenge None
Unfathomable Chasm
Land
Unfathomable Chasm enters the battlefield tapped.
: Add to your mana pool.
: Exile target Kraken, Leviathan, Octopus, or Serpent you control. Return it to the battlefield at the beginning of the next end step.
: Add 
to your mana pool.
See Challenge # 128.
"The depths of Ezan's seas contain enormous sea creatures that, luckily for Ezan's inhabitants, don't generally rise to the surface."
Oooh. Very flavorful.