According to Kreosan, the crazy microwave-stick's creators (and Darwin award contenders), this contraption is a microwave's magnetron on a stick, with a directional antenna to aim it. The result is a magic wand that can light up lights, blow up stereos, oh and also definitely kill you.
Kreosan describes his/their/its channel this way (Google translated from Russian):
Our channel video about unusual experiments with electricity, experiments and inventions. Here we share new ideas, different from the majority of habitual thinking.