This will probably get buried BUT there was a particular spectacular liar in my friend group back in sixth form who made all sorts of fantastical claims. Although my favourite is thus:

She used to go in secondary school in London. But it wasn't just a regular school OH NO. It was a spoopy spectacular creep fest made to give special snowflakes an extra special troubled background. According to her, it was in the rough parts so there was always police about. And sometimes, the police would -shock! horror!- take a pupil out of class for questioning. Except the pupil would never return. Gasp. She claimed that whenever they saw the police coming the entire class would hide in a vent in the back of the classroom and whoever was unlucky enough to not fit in would gt abducted and never return. That's right. Hordes of schoolchildren were abducted by the police in a school in London and nobody batted an eyelid. Yup.

She was also pretty damn delusional. She claimed that when she was dancing in a nightclub once, a burlesque dancer recruited her to be a burlesque dancer because she was so good at dancing (she was fat and most definitely not good at dancing... Or being attractive). Also one time she claimed the Mayor personally invited her and an equally nutso friend to a masquerade ball at the town hall.