Benthic Riverwinder

Benthic Riverwinder enters the battlefield with a
+1/+1 counter on it.
Landfall— Whenever a land enters the battlefield
under your control, Benthic Riverwinder
explores. (To explore, reveal the top card of your
library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then
put the card back or put it into your graveyard.)