kitten tilly had to be put down after inspectors found her ` clearly dying '
teenager threw the cat against walls , dangled her into bathwater by her tail and flushed her head in the toilet in disturbing footage .
cat was locked in the bathroom 24 hours a day and never fed .
16-year-old claimed he was ` accidentally ' high on ` white rhino ' marijuana .
attacker and owner , sarah reeves , given 10-year ban from keeping animals .