
Creatures with islandwalk can be blocked as though they didn't have islandwalk.
Undertow has 1 printing, first in Legends (1994). EDHREC ranks it #32,258 among Commander cards. It appears most in Stockman, Mad Fly-entist decks (1 on EDHREC).
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.