How can I purposely make linux unresponsive for a few seconds?

So basically I have a user who is running maven via jenkins jobs and they overload the machine and basically make it so ps doesn't respond. I want to play with solutions, is there any way to simulate this without actually overloading the system to that point? Is there a way to freeze the process to simulate the conditions?

I need to trip org.jenkinsci.plugins.workflow.steps.durable_task.DurableTaskStep.REMOTE_TIMEOUT timeout.