Cheapest priced copy (Assassin's Creed): $2.49 at Card Kingdom, near mint, their price list as of .
Leonardo da Vinci 
Legendary Creature — Human Artificer · 3/3 · Mythic · Assassin's Creed · #20
{3}{U}{U}: Until end of turn, Thopters you control have base power and toughness X/X, where X is the number of cards in your hand.
{2}{U}, {T}: Draw a card, then discard a card. If the discarded card was an artifact card, exile it from your graveyard. If you do, create a token that's a copy of it, except it's a 0/2 Thopter artifact creature with flying in addition to its other types.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $2.49 to $8.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Assassin's Creed | 20 | Mythic | $2.49 | $2.49 |
| Assassin's Creed | 118 | Mythic | $7.99 | $8.99 |
| Assassin's Creed | 118z | Mythic | — | — |
| Assassin's Creed | 193 | Mythic | — | — |
5 rulings from Wizards of the Coast
- 5 July 2024Except for the listed exceptions, the token copies exactly what was printed on the discarded card and nothing else.
- 5 July 2024The token is a Thopter artifact creature in addition to its other types. Its power and toughness are 0/2, and it has flying. These are copiable values of the token that other effects may copy.
- 5 July 2024If the copied card has {X} in its mana cost, X is 0.
- 5 July 2024Any enters-the-battlefield abilities of the copied card will trigger when the token enters the battlefield. Any “as [this artifact]” enters the battlefield or “[this artifact] enters the battlefield with” abilities of the copied card will also work.
- 5 July 2024The value of X is determined only as Leonardo’s first ability resolves. Once that happens, the value of X won’t change later in the turn even if the number of cards in your hand changes.