My Parents Are Aliens (1999) : 5x3

After Brian accidentally leaves the front door open, Brian and Sophie come home to find all their furniture stolen. Brian responds by morphing into 'The Cat' to steal furniture from other homes, and this becomes his latest hobby. Josh discovers Brian's secret and (predictably) uses it to his own advantage. Meanwhile, Sophie becomes obsessed with home security, putting traps everywhere (which are mostly triggered by the Josh rather than burglars) and fears about the burglar worry Lucy so much that she begins to wet the bed.