It's likely you're thinking about a different kind of Valentine's Day activity or item. Here are some possibilities:
* Valentine's Day Cards: Neopets has a dedicated section for buying and sending Valentine's Day cards. You can choose from pre-made cards or create your own.
* Valentine's Day Gifts: You can buy Valentine's Day themed gifts for your Neopet and send them to your friends.
* Mystery Gift: While there's no specific "mysterious Valentine's card," you can send a Mystery Gift which contains random items.
It's always a good idea to double-check the official Neopets website for the latest information on Valentine's Day events and activities.