Hillbilly Attack
Caro-Kann Defense
1.e4 c6 2.Bc4 d5 3.exd5 cxd5
White aims the bishop at f7 with 2.Bc4; after 2...d5 3.exd5 cxd5 the bishop is attacked and must move again.
Fun fact: Simon Williams, who advocates the line, credits the name to National Master Jack Young, who used it to describe the move's unrefined nature. Source
Practice this lineThe idea
2.Bc4 aims the bishop at f7, but after 2...d5 the d5 pawn is defended by both the c-pawn and the queen, so after 3.exd5 cxd5 White's bishop is attacked and has to move again. That lost time is why the line has a poor reputation, though it has become a surprise weapon in online blitz.
Plans for White
Move the bishop to safety, usually to b3 or to b5 with check, and develop quickly with Nf3, d4, Nc3 and castling. White's position is sound; it is simply a tempo behind the Exchange Variation, so active development matters more than ever.
Plans for Black
Black has gained a tempo and gets an easy game. Develop with ...Nc6 and ...Nf6, bring the bishop out to f5 or g4, and play ...e6. Black has the only pawn in the center for now, and solid, natural moves keep it there.
Watch out for
For Black, the Schaeffer Gambit. Many blitz players skip 3.exd5 and play 3.Bb3, offering a pawn: after 3...dxe4 4.Qh5 the queen and bishop both hit f7. Black must defend it, usually with 4...e6 or 4...g6.
For White, 3.exd5 cxd5 hands Black a free tempo. A check on b5 that Black blocks with a developing move doesn't win it back, so White needs to develop fast rather than move the bishop again.