If you skip to 17:08, he talks about a skull called Boom. What I’m wondering is, is there a difference between the Boom skull he talked about, and the Cowbell skull?
> http://www.youtube.com/watch?v=nsegu_SsIJE
>
> If you skip to 17:08, he talks about a skull called Boom. What I’m wondering is, is there a difference between the Boom skull he talked about, and the Cowbell skull?
I’m not aware of the exact changes Cowbell made to the explosion radius (but I know it applied to all explosive elements–grenades just being one part). Boom doubles the radius of explosions, so it could be fairly similar I suppose. 
It was confirmed at an interview with g4 that most skulls will act a little fimiliar to previos skulls.
The Cowbell skull multiplies physics impulses i.e. things will fly further when hit with force.
From what I gather, the Boom skull will double the radius of any explosions i.e. you will receive damage twice as far away from the origin of the explosion.
At least that’s what it sounds like to me :S