The trigger of Flamerush Rider is targeted
we are Venom!" P/T Number 55b Language English Legal Formats Alchemy, Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pioneer, Standard, Timeless, Vintage Rulings (9/19/2025) To determine whether it is legal to play a modal double-faced card, consider only the characteristics of the face you're playing and ignore the other face's characteristics
For example, you can't exile more than seven cards from your graveyard to cast Treasure Cruise unless an effect has increased its cost
The selling point of an effect like this is definitely the ceiling, and here the ceiling is a pre-combat trump card which produces lethal from far beyond the range your opponent expects for 1B
Use it to help reset the board or pull even farther ahead