EU countries are allowed to, by Treaty, expel EU citizens who moved there without the means to live there or a job.
However it’s incredibly rare and there really isn’t any general procedure to do it: each country does it (or not) it’s own way. This tends to be used for people caught sleeping or begging on the streets.
Further, for countries in the Schengen Area, they don’t even know you’re there unless you register, since you haven’t passed any border controls and thus aren’t in any database as having arrived but not departed.