If Silent Hallcreeper leaves the battlefield and then returns to the battlefield later, it will be a new object with no memory of the modes that were chosen when it was last on the battlefield
The most obvious is to mill your opponents deck from different angles with cards like Glimpse the Unthinkable, Kitsune's Technique, Umbris, Fear Manifest, Krang & Shredder, Tasha's Hideous Laughter or Space-Time Anomaly
You can banish this card from your GY, then target 1 "Synchron" monster in your GY
The Pokmon in this list possess a poison-related attack or ability that can be strategically used to wear down opponents and secure victories in competitive battles
She can return two of your trashed cards to the bottom of your deck for you to find later with Sakazukis heavy draw power while returning one to your hand to be used immediately after
Check out our guide on how to play MTG Commander