Ulasht plus the number of green creatures you control excluding
Ulasht is at least X.
Steps
Activate
Yahenni by sacrificing
Ulasht.
When
Ulasht dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to its replacement effect.
Resolve the
Yahenni ability.
Repeat.
Results
Infinite ETB.
Infinite LTB.
Infinite death triggers.
Infinite sacrifice triggers.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).