Hopefully, MTG Battle cards will get a bit more explanation there and answer the many burning questions that MTG community members now possess
Threshold is trivially easy to get to in decks that play rituals given that you play lots of instants and sorceries
Boomerang Energy can be discarded for Greninja exs Mirage Barrage and instantly return to Greninja ex, making the attack easier to chain in longer games
Yes, it feeds into all these other loops
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