This looks like lightning to me. Some lightning is cloud to cloud and can illuminate from above or inside and can be close to continuous for brief times. Cumulus clouds, the puffy ones, can have clear air in pockets between clouds.

This video could be explained by cloud to cloud lightning shining through a clear air gap onto a base layer. Which then becomes cloud to ground lightening traveling through virga (rain that doesn't fully reach the ground) that almost looks like a funnel cloud.

That helicopter is way, way too close to the storm for safety. 2 Miles from a wall cloud is the standard minimum.