It's true they get a stomach ache and if it's 85% or more they can die (Weekly lessons ep 4)

CHOCOLATE IS BAD FOR DOGS; THEY CAN END UP LIKE THIS; OR LIKE THIS WITH A LOT OF CACAO, IT MESSES UP THEIR STOMACHS; AND THAT'S WHY CLASS DARK CHOCOLATE SUCKS IF YOUR DOG GETS SICK SO WILL YOU; UNLESS IT'S WHITE CHOCOLATE THAT S*** IS FAKE WITH NO CACAO