Ratadrabik of Urborg | Leyline of Singularity

Cards

Cast
Dack's Duplicate by paying its mana cost. Choose to have it enter as a copy of
Ratadrabik.
Put
Dack's Duplicate into your graveyard due to the legend rule.
When
Dack's Duplicate dies,
Ratadrabik triggers, creating a token copy of
Dack's Duplicate that is a copy of
Ratadrabik but is a 2/2 Zombie in addition to its other types.
Repeat from step 2 using the
Dack's Duplicate token instead.

This combo produces a mandatory infinite loop that'll cause the game to end in a draw if it isn't interacted with.

Bracket tag

SpicyBracket 3-4+

Probably 3 or 4, but hard to classify

Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.

Popularity

decks on EDHREC

Variants

variants of this combo

Salt

Too few votes

How unfun this combo is to play against, from 0 to 4, as voted by Commander Spellbook users. Scores are refreshed every couple of hours.