Stray Bead

Tap an untapped creature you control: That
creature explores. (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 the creature, then
put the card back or put it into your graveyard.)
At the beginning of your end step, if you both
own and control three other cards named Stray
Bead, meld them into String of Beads.
A deck can have any number of Stray Beads.