The ability that defines Barrowgoyf's power and toughness works in all zones, not just the battlefield
The sequence works like this: Sacrifice Persist Creature A Persist and Long Feng both trigger
Feel the Card Real cards have a certain weight and texture
He believed that kids were being "brainwashed", and said: "I have had parents tell me that they cannot get their kids to do anything except Pokmon, so this stuff seems to really capture their minds, in a way"
Famously, she reflected an overwhelmingly powerful lightning strike from Kolaghan herself that would've killed many hundreds on impact
You of course also have the option later in the game to put the curse somewhere else like on a creature that is already incapacitated in one way or another, and a 3/2 body is imposing enough that the Hexmage is likely to usually matter