You control a face-down creature whose front face is a permanent card.
Steps
Donate
Karlov Watchdog to an opponent.
During the opponent's turn, activate
Woe Strider by sacrificing a face-down creature you control.
When the creature dies,
Yarus's second ability triggers, returning it from your graveyard to the battlefield face-down as a 2/2 creature, and then not turning it face-up due to
Karlov Watchdog.
Resolve the
Woe Strider ability.
Repeat from step 2.
Results
Infinite LTB.
Infinite ETB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite scry 1.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).