Usually that's a mana cost, but it could also be something like discarding a card or paying life
While many in the counterfeit card community disavow selling fake cards to players, the fact remains that simply by handing your money over to counterfeiters, you are helping to improve counterfeit cards, make them more realistic, and assist other people in scamming other players
Its packed full of goodies and juices for all of us
If an effect states that a creature or land enters the battlefield tapped unless a condition is met, Thalias last ability has it enter tapped even if that condition is true
The cards primary attack, Continuous Fireball, mirrors its darker narrative
It can do the same each time it attacks, and it can help keep itself alive during attacks thanks to its ability