Informal name for a woodlouse or pill-bug, a type of insect that lives predominantly in damp conditions e.g: under paving slabs and logs.
Alex: Ew gross I just stepped on something crunchy outside, I think it was a bug.
Katy: Was it slimey? Could have been a snail.
Lynda: Awww no, you've just squashed a massive peelabola!