Goat format ruling
Ordeal of a Traveler

Card effect (current official text)When an opponent's monster declares an attack: Your opponent chooses 1 random card in your hand and calls the type of the card (Monster, Spell, or Trap), and if they call it wrong, return the attacking monster to the hand.
Rulings
- You can activate the effect of Ordeal of a Traveler each time your opponent attacks.
- You must show the card your opponent selects to your opponent.
- If your opponent calls it right, the attack resolves normally.
- You cannot activate Ordeal of a Traveler’s effect if you have no cards in your hand.
- When Ordeal of a Traveler & Fairy Box are both applying, Fairy Box (mandatory) is step 1 of the chain, and Ordeal of a Traveler (optional) is step 2.
- When you activate Ordeal of a Traveler’s effect as a chain to Magic Cylinder, since Ordeal of a Traveler resolves first, if your opponent guesses incorrectly then the attack does not resolve and the effect of Magic Cylinder disappears. If multiple copies of Ordeal of a Traveler are applying, their effects are cumulative.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.