duelist nexus booster box Sealed Case (12x Boxes) EU English 1st Edition – Evolution TCG expanding the range of strategies Duelist Nexus display 24 Yu-Gi-Oh

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)

But considering their nod to earlier monochrome full-art cards like Latios, Latias, Articuno, and Terrakion, additional ones may be coming

Currently I have a near complete collection of Japanese XY booster boxes 11/16 and 3/14 for my BW era boxes

No idea what the kid is saying but yes, as you noticed the location of the rear flap and the crimp look like a match here