Cheapest priced copy (The Lost Caverns of Ixalan Commander): $7.99 at Card Kingdom, near mint, their price list as of .
Contest of Claws 
Sorcery · Rare · The Lost Caverns of Ixalan Commander · #12
Target creature you control deals damage equal to its power to another target creature. If excess damage was dealt this way, discover X, where X is that excess damage. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $7.99 to $9.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan Commander | 12 | Rare | $7.99 | $8.99Out of stock |
| The Lost Caverns of Ixalan Commander | 24 | Rare | $9.49 | $9.99 |
10 rulings from Wizards of the Coast
- 10 November 2023Some spells and abilities that cause you to discover may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve and you won't discover.
- 10 November 2023When you discover, you must exile cards. The only optional part of the ability is whether you cast the exiled card or put it into your hand.
- 10 November 2023If you discover an adventurer card, split card, or modal double-faced card, you might be able to cast that card with either set of characteristics depending on the effect's discover value. For example, if you discover 4 and reveal Galvanic Giant (an adventurer card from Wilds of Eldraine with a mana value of 4), you could cast Galvanic Giant, but not Storm Reading (its Adventure, which has a mana value of 7). If you discover 7 and reveal Galvanic Giant, you could cast either Galvanic Giant or Storm Reading.
- 10 November 2023Excess damage has been dealt to a creature if the damage dealt to it is greater than lethal damage. Usually, this means damage greater than its toughness, although damage already marked on the creature is taken into account.
- 10 November 2023A spell's mana value is determined only by its mana cost. Ignore any alternative costs, additional costs, cost increases, or cost reductions.
- 10 November 2023If you can't cast the discovered card (perhaps because there are no legal targets for the spell), you'll put it into your hand.
- 10 November 2023The mana value of a split card is determined by the combined mana cost of its two halves. If discover allows you to cast a split card, you may cast either half (as long as its mana value is less than or equal to the effect's discover value) but not both halves.
- 10 November 2023You exile the cards face up. All players will be able to see them.
- 10 November 2023If you cast a spell "without paying its mana cost", you can't choose to cast it for any alternative costs. You can, however, pay additional costs. If the spell has any mandatory additional costs, you must pay those to cast it.
- 10 November 2023If the discovered card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.