Cheapest priced copy (Modern Horizons): $3.49 at Card Kingdom, near mint, their price list as of .
Mist-Syndicate Naga 
Creature — Snake Ninja · 3/1 · Rare · Modern Horizons · #58
Ninjutsu {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, create a token that's a copy of this creature.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $3.49 to $8.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons | 58 | Rare | $3.49 | $8.99 |
9 rulings from Wizards of the Coast
- 14 June 2019Although the Ninja is attacking, it was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example).
- 14 June 2019If a creature in combat has first strike or double strike, you can activate the ninjutsu ability during the first-strike combat damage step. The Ninja will deal combat damage during the regular combat damage step, even if it has first strike.
- 14 June 2019The ninjutsu ability can be activated only after blockers have been declared. Before then, attacking creatures are neither blocked nor unblocked.
- 14 June 2019The token won’t copy counters, Auras, or Equipment on Mist-Syndicate Naga, nor will it copy other effects that have changed its power, toughness, types, color, or so on. Normally, this means the token will simply be a Mist-Syndicate Naga. But if any copy effects have affected Mist-Syndicate Naga, they’re taken into account.
- 14 June 2019The token will have Mist-Syndicate Naga’s ability. It will also be able to create copies of itself.
- 14 June 2019The ninjutsu ability can be activated during the declare blockers step, combat damage step, or end of combat step. If you wait until after the declare blockers step, because all combat damage is dealt at once, the Ninja won’t normally deal combat damage.
- 14 June 2019As you activate a ninjutsu ability, you reveal the Ninja card in your hand and return the attacking creature. The Ninja isn’t put onto the battlefield until the ability resolves. If it leaves your hand before then, it won’t enter the battlefield at all.
- 14 June 2019The creature with ninjutsu enters the battlefield attacking the same player or planeswalker that the returned creature was attacking. This is a rule specific to ninjutsu; in other cases, when a creature is put onto the battlefield attacking, that creature’s controller chooses which player or planeswalker it’s attacking.
- 14 June 2019If Mist-Syndicate Naga leaves the battlefield before its triggered ability resolves, the token will still enter the battlefield as a copy of Mist-Syndicate Naga, using Mist-Syndicate Naga’s copiable values from when it was last on the battlefield.