Izzy is imitating a fictional character with the dog collar from the movie Unleashed where Jet Li plays a character that is held back with a dog collar and he will only start fighting when he is unlocked from the collar. So i would not say that it is a serious level of thinking as he is pretending to be a fictional movie character 
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Yeah, you are right. But it was kinda cool at some point with his angry dead-looking face..Such an amazing fight because of such an unexpected ending. Performance in the first round from both of them was equal but Pereira started the second round with more pressure and when he had Adesanya pushed in the corner and striking, I was like, yeah, Adesanya is done and Pereira wins again but holy shit, Adesanya gave him an amazing strike, it was a great knockout. His strike was so fast that I was kinda confused, then slowed down video, repeat that scene again and his strike was so fast that it was still hard to view it well
Definitely it was a great fight and congrats to Adesanya, he unleashed the beast!