Activate Saffi by sacrificing it, targeting Fiendish Panda.
Activate Viscera Seer by sacrificing Fiendish Panda.
When Fiendish Panda dies, its second ability and Saffi trigger.
Resolve the Saffi trigger, returning Fiendish Panda from your graveyard to the battlefield.
Resolve the Fiendish Panda trigger, returning Saffi from your graveyard to the battlefield.
Resolve the Viscera Seer ability, causing you to scry 1.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite scry 1

Saffi Eriksdotter

Fiendish Panda

Viscera Seer

Activate Fiendish Panda by using Walking Ballista's ability by removing a +1/+1 counter from it, dealing 1 damage to any target and causing you to gain 1 life due to its lifelink.
Fiendish Panda triggers, putting a +1/+1 counter on it.
Repeat.

Combos with "Fiendish Panda"