Merfolk Surveyor [Unknown Event]

When Merfolk Surveyor enters the battlefield, explore-clash. If you win the explore-clash, gain 3 life. (To explore-clash, you and an opponent each reveal the top card of your respective libraries. Put any lands revealed this way into their owner's hands. Put a +1/+1 counter on this creature for each nonland card revealed this way. Then, each player who didn't get a nonland puts the card back or into their graveyard. You win the explore-clash if the mana value of your revealed card was higher.)