Vesuvan Shapeshifter

Mana cost: {3}{U}{U}
Type: Creature — Shapeshifter
Power / toughness: 0 / 0
Set: Commander 2019 #101 (rare)
Price: $0.38 USD

As this creature enters or is turned face up, you may choose another creature on the battlefield. If you do, until this creature is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."
Morph {1}{U}

Vesuvan Shapeshifter has 4 printings, first in Time Spiral (2006). EDHREC ranks it #7,570 among Commander cards. It appears most in Kadena, Slinking Sorcerer decks (6,744 on EDHREC). 1 public deck on TCG runs it. It has 6 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: not legal
standard: not legal
brawl: not legal

Public decks that run Vesuvan Shapeshifter

Faceless Menace - Commander 2019, led by Kadena, Slinking Sorcerer

Commanders that run Vesuvan Shapeshifter most

Deck counts from EDHREC.

Often played with Vesuvan Shapeshifter

Cards that show up in the same decks on EDHREC.

Rulings

2021-03-19: If a copied creature is copying something else, Vesuvan Shapeshifter uses the copiable values of that creature. In most cases, Vesuvan Shapeshifter will copy whatever that creature is copying.
2021-03-19: Vesuvan Shapeshifter copies exactly what is printed on the creature it's copying and nothing else (unless it's copying a creature that's copying something else or that's a token; see below). It doesn't copy whether a creature is tapped or untapped, whether it 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. Most notably, if it copies a creature that's not normally a creature, it won't be a creature.
2021-03-19: If something copies Vesuvan Shapeshifter, the new copy will also have the triggered ability to turn it face down. However, once face-down, it won't have Vesuvan Shapeshifter's morph ability, so it can't be turned face up unless whatever it's copying also has a morph ability.
2021-03-19: If a copied creature has {X} in its mana cost, X is 0.
2021-03-19: Any enters-the-battlefield abilities of the copied creature will trigger if Vesuvan Shapeshifter is entering the battlefield. Any "As [this creature] enters the battlefield" or "[This creature] enters the battlefield with" abilities of the copied creature will also work. If a Vesuvan Shapeshifter becomes a copy of a creature after it's already on the battlefield, these abilities won't apply as Vesuvan Shapeshifter becomes a copy since it's not entering the battlefield; instead, any "As [this creature] is turned face up" or "When [this creature] is turned face up" abilities will apply.
2021-03-19: If a copied creature is a token that isn't a copy of something else, Vesuvan Shapeshifter copies the original characteristics of that token as stated by the effect that created it. Vesuvan Shapeshifter isn't a token in this case.