I can do one better for exit. The Solaris kernel debugger KDB can be used at runtime for inspecting some stats and also to change some global configurable variables.

For whatever reason if you type a variable/symbol it assigns it the value 0. If you type exit nothing happens immediately but as soon as the next process exits usually a few seconds to 10s of seconds later the entire system kernel panics on a null pointer de-reference.

Kernel paniced our production ZFS filer twice before I cottoned on. Newer releases special cased “exit” not to do that.