SIGSTOP

Freezes the process wherever it stands — and takes no refusal.

SIGKILL's non-negotiable partner: one freezes, the other eliminates, and neither can be caught, blocked or ignored. The process stops wherever it stands, with no warning and no chance to tidy the scene first.

It is the administrative pause: holding a heavy backup while the server rides out a peak, freezing a suspicious process to examine it calmly. The thaw is SIGCONT — and, in between, the process wears a T in ps.

$ kill -STOP $(pidof -s ffmpeg)
$ ps -o pid,stat,comm -p $(pidof -s ffmpeg)
    PID STAT COMMAND
   9021 T    ffmpeg
$ kill -CONT $(pidof -s ffmpeg)

T for stopped: frozen until further notice.