They allow you to cast spells that cost four or more mana from the top of your library
Again, if this works, you could use it to carefully watch the animation, head back into the game and pick the card of your choosing each time

Full Decklist 5 Forest 5 Island 5 Swamp Agent Frank Horrigan Alpha Deathclaw Arcane Signet Ash Barrens Atomize Biomass Mutation Bloatfly Swarm Branching Evolution Casualties of War Cathedral Acolyte Command Tower Contagion Clasp Contaminated Drink Corpsejack Menace Cultivate Darkwater Catacombs Drowned Catacomb Evolving Wilds Exotic Orchard Farseek Feral Ghoul Fetid Pools Find // Finality Forced Evolution Fraying Sanity Glowing One Guardian Project Hancock, Ghoulish Mayor Hardened Scales Harmonize Harold and Bob, First Numens Hinterland Harbor Inexorable Tide Infesting Radroach Inspiring Call Jason Bright, Glowing Prophet Lily Bowen, Raging Grandma Lumbering Megasloth Marcus, Mutant Mayor Mariposa Military Base Mirelurk Queen Mortuary Mire Mutational Advantage Nesting Grounds Nightkin Ambusher Nuclear Fallout Nuka-Nuke Launcher Opulent Palace Overflowing Basin Path of Ancestry Piper Wright, Publick Reporter Power Fist Putrefy Radstorm Rampaging Yao Guai Rampant Growth Raul, Trouble Shooter Recon Craft Theta Screeching Scorchbeast Sol Ring Strength Bobblehead Strong, the Brutish Thespian Struggle for Project Purity Sunken Hollow Tainted Isle Tainted Wood Talisman of Curiosity Talisman of Dominance Talisman of Resilience Tato Farmer Temple of Deceit Temple of Malady Temple of Mystery Temple of the False God Terramorphic Expanse The Master, Transcendent The Necropolis The Wise Mothman Tireless Tracker Vexing Radgull Viridescent Bog Watchful Radstag Winding Constrictor Woodland Cemetery Young Deathclaws Hail, Caesar Throw Your Own Creatures To The Slaughter Fallout might be a world of mutants, robots, and monsters, but perhaps the biggest threats in the wasteland are other people

Perfect for hobby shops, convention centers, entertainment venues, and specialty retail spaces
Wash Out should see more play, as its often a Rivers Rebuke for four mana
FAQ What was the very first Pokmon card ever made