It gets complicated because of the different editions and versions, but well break it down as easily as possible
From here, I selected the Umbreon VMAX (Alternate Art Secret) from the search results
With the Tiger, we can be guaranteed to cast it next turn and then have Prey Upon available on our untap step as long as the Tiger still draws breath
Prerelease pickup starting 11/14/25 Universes Beyond Avatar: The Last Airbender Each Collector Booster contains 15 Magic: The Gathering cards: Collector Boosters may contain these cards: TLA 1281, 287392
If heads, that Trainer card was completely negated and placed directly back on top of the opponent's deck, completely burning their turn's momentum
Not adding to the board can be a liability, and this format does feel like it will be a fast one so you never really want more than one of these