Stuck in the lake

At the beginning of your upkeep, choose 1:
Paddle back: return a card with a mana value
of 6 or less to the battlefield or to your hand. Put a back-to-the-shore counter on this enchantment.
Jump in: remove a back-to-shore counter from this enchantment. Mill 1
If this enchantment has 3 or more back-to-shore counters on it, sacrifice it.