Basically, picture a regular cargo plane . . . with a huge forehead . . . that's designed to seat a herd of dinosaurs . . . and actually flies . . . in the sky . . . on Planet Earth.
Thanks to the power of Reddit's devoted followers, the mystery was solved in less than three minutes by a commenter who send a Wikipedia link to the Super Guppy — a massive NASA aircraft used to ferry parts for the International Space Station.
For all you space buffs out there, check out NASA's detailed history of Super Guppy on the agency's website.