It's not often that you see an uncommon that's stronger than rare and mythic rare cards, but it does happen - and you'll probably have plenty of these cards in your deck, anyway
While it doesnt end games itself, theres a long list of other, single cards that absolutely do when soulbound with it
In addition to being a slight rewriting of the classic Jingle Bells line, the part that says "sing a slaying song tonight" is modeled on the fact that "sleigh" and "slay" sound phonetically identical to each other, and the effect involves you 'slaying' some creatures (or at least attempting to)
Section 5 Summary Input: One playing of Millikin Output: Lots of reuse of the two Rust Ticks Layer count: For each Bloodbond March, for each Clash of Realities on a new Mimic Vat, for each Guilty Conscience on Mimic Vat, for each Rite of Passage putting counters on Mimic Vat, for each Doubling Season on the Rite of Passage counters added to Mimic Vat, for each Rings of Brighthearth on Sinking Feeling's ability while it's attached to Mimic Vat, for each Rings of Brighthearth on Mimic Vat's ability, for each Clash of Realities on Millikin, for each Guilty Conscience on Millikin, for each Rite of Passage putting counters on Millikin, for each Doubling Season on the Rite of Passage counters added to Millikin, for each Rings of Brighthearth on Sinking Feeling's ability while it's attached to Millikin...12
Information about this event is currently limited, so its important to keep an eye on official Pokemon social media channels to keep yourself in the loop
In a pinch, you can even bounce your own permanent to save it or trigger landfall
