SAN BRUNO, Calif. (AP) -- YouTube is trying to prevent otherwise bright people from doing dangerous things.

The video-sharing network owned by Google is cracking down on harmful or dangerous pranks.

Updated policies no longer allow challenges that present ``an apparent risk of death'' and ban content featuring children ``participating in dangerous challenges that pose an imminent risk of injury or bodily harm.''

YouTube also says it is drawing the line on content that ``intends to incite violence or encourage dangerous or illegal activities'' that have a risk of serious harm or death. They include bomb making or pranks that put people in physical danger.

A recent ``Bird Box challenge'' featured videos of people engaging in activities while blindfolded.

People also were sickened in a challenge that involved eating Tide detergent pods.