Was it an illusion? Was it a ghost? Was it just plain ol' physics?

Whatever the cause*, what's really important is that this pint just spontaneously exploded in the middle of a Drogheda pub on St Patrick's Day. And it was all caught on camera.

The video was posted on the Facebook page of Barney Macs – and even more entertaining than the explosion itself is the collective reaction of the people who were in the pub at the time.

You can watch here...

* It was definitely physics. Let's not even debate this.