Waterwind Scout

If an ability instructs a creature to explore, its controller reveals the top card of their library. If it's a land card, they'll put it into their hand. Otherwise, they'll put a +1/+1 counter on that creature, then choose to either leave that card on top of their library or put it into their graveyard.

Map tokens are a kind of predefined token. Each one is a colorless artifact with the artifact subtype Map and the ability "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery."

Once an ability that causes a creature to explore begins to resolve, no player may take any other actions until it's done. Notably, opponents can't try to remove the exploring creature after you reveal a nonland card but before it receives a counter.