Hmm...
I vote for, well, this entire thread.
#1 - Video for ATOT to enjoy is a must.
#2 - Telling him off, definitely, especially on said video.
#3 - Contact the old landlord and let him know what tenant is doing.
#4 - Get a restraining order.
#5 - ...
#6 - Profit.
All of these (except #5 and #6) have already been suggested, so you should be good.