Why yes, that is Mario possessing a T. rex in the new Super Mario Odyssey trailer
Seriously, if you thought Mario showing up in “New Donk City” and running around with realistic-looking humans was weird, just wait to see the new features of Super Mario Odyssey Nintendo showed off in the game’s latest trailer. Apparently the reason Mario’s hat now has eyes is that it’s been possessed by Cappy, a ghost that looks like a top hat. Although it appears Mario himself is able to resist its influence, the heroic plumber can use this demonic cap to manipulate objects and possess living things—including the citizens of New Donk City and even a freakin’ dinosaur. Mario has to use this ghoulish new ability to collect moons, not stars, across various worlds and power his airship, named The Odyssey, so he can save Princess Peach before Bowser marries her. Also, Pauline, the damsel in distress from the original Donkey Kong, is the mayor of New Donk City, which is pretty great.
In addition to the jazzy new trailer, which revealed the game’s release date as October 27, Nintendo showed more than 30 minutes of footage direct from the game during its E3 live broadcast, along with commentary from its director and some Nintendo staff.