This effect is permanent and cannot be undone, save by restore control effects, bouncing to hand, or flickering
The card name is haunting Wind and the flavor text talks about the device the spirits are surrounding, but does that mean the spirits came in with the wind
If Soul Warden enters at the same time as one or more other creatures, its ability will trigger for each of those other creatures

Abundance Agent's Toolkit Alhammarret's Archive Alms Collector Archmage Ascension Artist's Talent Asmodeus the Archfiend Blood Scrivener Case of the Pilfered Proof Dakmor Salvage Dark Dabbling Darkblast Enduring Renewal Eruth, Tormented Prophet Family's Favor Fasting First-Sphere Gargantua Fisher's Talent Flotsam // Jetsam Forbidden Crypt Golgari Brownscale Golgari Grave-Troll Golgari Thug Grave-Shell Scarab Greater Mossdog Heroic Sacrifice High Score Hullbreacher Immortal Coil Island Sanctuary Izzet Generatorium Jace, Wielder of Mysteries Jaya Ballard Laboratory Maniac Lashknife Barrier Leader, Super-Genius Lich Life from the Loam Living Conundrum Mangara's Tome Meat Locker // Drowned Diner Moldervine Cloak Necrodominance Necroplasm Nemata, Primeval Warden Nightmare Void Notion Thief Obstinate Familiar Ormos, Archive Keeper Out of the Tombs Ozolith, the Shattered Spire Parallel Thoughts Peregrin Took Personal Decoy (playtest) Phial of Galadriel Plagiarize Pursuit of Knowledge Quantum Riddler Ral's Vanguard (playtest) Retriever Phoenix Rigo, Streetwise Mentor Rime Chill Sages of the Anima Scrapwork Mutt Scrapwork Rager Shambling Shell Sharae of Numbing Depths Shenanigans Snake Umbra

3: Fear of Lost Teeth All of the Fears are depicted incredibly, with their monstrous creeping forms being a creative way to visually capture the feeling of having these fears yourself