Groundhog

Groundhog in its burrow

The Groundhog is a passive entity that hides in its hole when the player approaches it. If the date on your computer is set to February 2nd (Groundhog Day), the Groundhog will be out of its burrow and will give you golden elixir that gives you a permanent golden heart which behaves exactly like a red heart container. This can be repeated a maximum of four times for the next four years, giving you four golden hearts.