Other forms: wildcat strikes
If a group of factory workers goes on strike without any planning, organization, or vote, it's called a wildcat strike.
Use the phrase wildcat strike when you're talking about a strike that's not approved by a union or sanctioned by any group or even a vote among workers. When people go on strike, they refuse to work as a protest against unfair or unsafe working conditions. When you talk about a wildcat strike, you're using wildcat to mean "untamed or unruly," just like an actual wild animal.