Serious question: is it pronounced TeSla or TeZla? I've always heard/said the former, so I assume the guy in the video is deliberately doing the "z" just as an affectation/mocking the way some people say some words (you know, like the way you people in England mispronounce "jaguar", making it a 6-syllable word).
*ducks*
Or
is it TeZla?