Attraction
Attraction is forcing a piece, often the king, onto a specific square so a follow-up tactic works.
The first move looks like a sacrifice. The second move only exists because the piece now stands on the new square — a fork, a smothered mate, or a discovered check.
Qg8+ is protected by the knight on h6, so the king cannot take. The rook is attracted to g8. After Rxg8, Nf7 is smothered mate. The queen was spent to put the rook on the square that boxes the king in.
If you are calculating a mate and one enemy piece is on the wrong square, ask whether a check can drag it there.