Day 21, glub glub glub

Threepony, are you insane,
Or just suffering from a hoof to the brain?
You say you can hold your breath for ten minutes,
But is there a reason to test your limits?
It wouldn't be half as bad if you could swim,
But into the ocean you were thrown on a whim.
Would you just pick up that stupid idol,
Before you dallying becomes suicidal.
Without it's tether you could walk to shore,
And you won't become undead pirate lore.