So, what do you do on a Mac when a process (as opposed to an application) is hogging CPU, swamping your machine, and you need to kill it?

I know you can use top or open Applications > Utilities > Activity Monitor and kill it from there.

But what happens when the process is already using so much CPU that doing either of those tasks is impossible?

On Windows, you can just do Ctrl/Alt/Delete and the process list will reliably open. So no matter how much your computer is thrashing, you always have access to the list of processes.

On Mac OS, there's Cmd/Alt/Escape, which reliably shows running applications. Fine when it's an application causing the problem. But: what do you do if it's a process?