Mordenkainen’s Faithful Hound. Doesn’t move, but does it occupy it’s space?

@JeremyECrawford Mordenkainen’s Faithful Hound. Doesn't move, but does it occupy it's space? Invisible, so does it have adv on attacks?

— Jeff Sorensen (@DelugeIA) August 25, 2016

Mordenkainen's faithful hound doesn't occupy its space. And it does benefit from being invisible. #DnD https://t.co/SiWHdenQ25

— Jeremy Crawford (@JeremyECrawford) August 25, 2016