The terrorists expect to be stopped by police, but they ignore them by slipping them a few bucks.
So far, so good. They plan to enter Rio and blow up a market. But when they get there, it's an empty, ruined square. Angry, the terrorists see a woman on the street and rape her, only to discover that she has a penis.
They've been going 0-2 Brazil, so they head over to the nearest school to shoot some children. When they get there, they hear gunfire. It's the local police force fighting some drug pushers.
There was actually a massive scandal in here because of an ISIS threat to bomb some shit during the olympic games, and a drug pusher gang from Rio went on to take a pic of them all armed with a taunt as a caption to them.
More hilariously, the phone number of an alleged ISIS member in Syria leaked, and people spammed the guy's WhatsApp with memes. I doubt it's true, but hilarious anyway.