Cheapest priced copy (Duskmourn: House of Horror Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Phenomenon Investigators 
Creature — Human Detective · 3/4 · Rare · Duskmourn: House of Horror Commander · #65
As this creature enters, choose Believe or Doubt.
• Believe — Whenever a nontoken creature you control dies, create a 2/2 black Horror enchantment creature token.
• Doubt — At the beginning of your end step, you may return a nonland permanent you own to your hand. If you do, draw a card.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duskmourn: House of Horror Commander | 38 | Rare | $0.49 | — |
| Duskmourn: House of Horror Commander | 65 | Rare | $0.49 | — |
One ruling from Wizards of the Coast
- 20 September 2024If you somehow control Phenomenon Investigators and no choice was made for it (perhaps because another permanent on the battlefield became a copy of it, or it was manifested and later turned face up), it has neither of the two triggered abilities, no matter how much you want to believe (or doubt).