I'm pretty sure HELOCs can be called any, iirc, but I'm not sure if fail to pay the call means they put a lien on your house or force you into foreclosure.

When people say "you should buy real estate as an investment because you can't live in your brokerage account" and then do crazy stuff with their equity that they wouldn't even dream of when investing (e.g. Boglehead investors who HELOC for some net negative remodel) it really blows my mind...