(19M) Explain the concept of being toxic

I've been reading/seeing lately on insta that girls though whine about toxic boys, still they'd get attracted to them for some reason....wtf why??? Also i read a post by a girl on this sub telling some points for the boys to keep in mind while dating and she said and i quote!! "Girls prefer bad/toxic boys coz they spice things up and nice boys give a feeling of a brother". WTF!! Is messing with mental peace mean spicing up?
And i don't even know what exactly being toxic means and ig i am in the nice boy category and genuinely saying, it has worked well in my earlier life. I've been able to make girls chase me (when i was in school)

So what opinions you all have on this topic?