P/T Set Number 73 Language Portugus Legal Formats Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Timeless, Vintage Not Legal Formats Alchemy, Pauper, Pioneer, Standard Rulings (11/17/2017) Swampwalk is a keyword ability that means "This creature can't be blocked if defending player controls a Swamp." Most nonbasic lands don't have basic land types, even if they produce colored mana
That helps, since they more/less need their hand to keep the opponent in check (see Dance Princess, Gungnir and a lot of other key cards)
If the creature is in an appropriate zone as the trigger event occurs but leaves that zone, the ability wont do anything as it resolves
And the artwork, I mean besides the Manga Art rare of this set being the one and only Silvers Rayleigh, Jewlery Bonney an Charlotte Pudding also feature with special artworks which really bring Eiichiro Odas visions to life