Merrow Harbinger LRW-73/5075 (The List Reprints)

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

NM - $6.00
LP - $4.50
MP - $3.50
HP - $2.50
DMG - $1.50