It was a friend's pet. It was playing around on the floor where we were sitting, nibbling on Scarlett's feet while she was grabbing it with her toes.
She squeezed it harder progressively and started squishing it under her foot. It was squealing but she was fascinated and didn't stop.
She must have crushed some bones because there was a crunch, blood and it stopped moving.
We told my friend we found it like that, then gassed it with nitrous oxide to finish the job.
Later she told me it made her feel powerful.