The Fork (The Double-Paw Strike)
A single piece attacks two or more enemy targets simultaneously. The opponent can usually only save one, allowing you to capture the other.
The Royal Fork (e.g. Knight on c7 checking the King on e8 while threatening the undefended Rook on a8 or Queen on d8).
Parry by moving the more valuable piece with check or counter-attacking an even higher-value target.