Cheapest priced copy (Innistrad: Crimson Vow): $0.59 at Card Kingdom, near mint, their price list as of .
Runo Stromkirk // Krothuss, Lord of the Deep 
Legendary Creature — Vampire Cleric // Legendary Creature — Kraken Horror · 1/4 · Rare · Innistrad: Crimson Vow · #316
Flying
When Runo enters, put up to one target creature card from your graveyard on top of your library.
At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If a creature card with mana value 6 or greater is revealed this way, transform Runo.
Flying
Whenever Krothuss attacks, create a tapped and attacking token that's a copy of another target attacking creature. If that creature is a Kraken, Leviathan, Octopus, or Serpent, create two of those tokens instead.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $0.59 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad: Double Feature | 513 | Rare | $0.69 | $3.49 |
| Innistrad: Crimson Vow Promos | 246s | Rare | — | $0.79 |
| Innistrad: Crimson Vow | 246 | Rare | $0.59 | $0.79 |
| Innistrad: Crimson Vow | 316 | Rare | $1.49 | $3.99 |
| Innistrad: Crimson Vow | 327 | Rare | $1.29 | $2.49 |
7 rulings from Wizards of the Coast
- 19 November 2021If the copied creature was copying something else, the token enters the battlefield as whatever that creature was copying.
- 19 November 2021Although the token is attacking, it was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example, like training).
- 19 November 2021The token copies exactly what was printed on the original creature and nothing else (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that creature has any counters on it or Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on. Notably, it doesn't copy any effects that may have turned a noncreature permanent into a creature. If the token isn't a creature as it enters the battlefield, it won't be attacking.
- 19 November 2021If the copied creature is a token, the token created by Krothuss copies the original characteristics of that token as stated by the effect that put it onto the battlefield.
- 19 November 2021Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any “As [this creature] enters the battlefield” or “[This creature] enters the battlefield with” abilities of the copied creature will also work.
- 19 November 2021You choose which opponent or opposing planeswalker the token is attacking as you put it onto the battlefield. It doesn't have to be the same player or planeswalker Krothuss, Lord of the Deep is attacking.
- 19 November 2021If the copied creature had {X} in its mana cost, X is 0.