You Tell Me ...

I've been intending to blip this shrub for a while. I pass it frequently near to work when walking at lunchtime. The red bracts start off as single chains. Then as the berries inside them swell to full size and the bracts open right up, this great mass is produced, with the berries starting red and maturing to black. It's fascinating to watch over the weeks as it goes through its different stages.
I've absolutely NO idea what it is! So if anyone out there knows, please - you tell me!
(I've managed a music link at last today, for the first time in a while - You Tell Me is the name of a Tom Petty track).