You don’t mess with a mamma bear and her cubs, as these tourists at Yellowstone National Park found out the hard way.

A black bear and her three cubs sent tourists running when they appeared on a bridge lined with sightseers earlier this week.

Some of the onlookers seemed confused and conflicted about whether to run or not.

But as you can see when someone yelled, “Go! Keep moving!” you can clearly see the panic starts to kick in.