Sevinne, the Chronoclasm

Mana cost: {2}{U}{R}{W}
Type: Legendary Creature — Human Wizard
Power / toughness: 2 / 2
Set: Commander 2019 Oversized #49 (mythic)

Prevent all damage that would be dealt to Sevinne.
Whenever you cast your first instant or sorcery spell from your graveyard each turn, copy that spell. You may choose new targets for the copy.

Sevinne, the Chronoclasm has 2 printings, first in Commander 2019 (2019). EDHREC ranks it #20,644 among Commander cards. It appears most in Niv-Mizzet, Supreme decks (528 on EDHREC). 1 public deck on TCG runs it. It has 8 official rulings.

Legality

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

Public decks that run Sevinne, the Chronoclasm

Mystic Intellect - Commander 2019, led by Sevinne, the Chronoclasm

Commanders that run Sevinne, the Chronoclasm most

Deck counts from EDHREC.

Niv-Mizzet, Supreme: 528 decks
Vadrok, Apex of Thunder: 131 decks

Often played with Sevinne, the Chronoclasm

Cards that show up in the same decks on EDHREC.

Rulings

2019-08-23: You can't choose to pay any additional costs for the copy. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.
2019-08-23: The copy that Sevinne's ability creates is created on the stack, so it's not "cast." Abilities that trigger when a player casts a spell won't trigger. Any of that spell's effects that apply only if it was cast from a graveyard won't apply.
2019-08-23: Sevinne's ability will copy any instant or sorcery spell, not just one with targets.
2019-08-23: If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copy will have the same mode or modes. You can't choose different ones.
2019-08-23: If you cast an instant or sorcery spell from your graveyard before Sevinne enters the battlefield during the same turn, its last ability can't trigger that turn.
2019-08-23: If the spell that's copied has an X whose value was determined as it was cast, the copy has the same value of X.
2019-08-23: The copy will have the same targets as the spell it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. The new targets must be legal.
2019-08-23: A copy is created even if the spell that caused Sevinne's ability to trigger has been countered by the time that ability resolves. The copy resolves before the original spell.