As I Joined the Queue

It was a wonderful, bright Summer's day. I was in the park running around and generally having a super time. Out of the corner of my eye, I spotted an ice-cream van!

As I joined the queue, something very strange started to happen...

I was almost at the front ready to place my order when the ice cream van started to shutter and shake.

WRRRRRRR!

"Oh no," muttered the ice cream man, "Not again."

Suddenly, in an enormous explosion, the ice cream van completely blew up! The ice cream man shot into the air and sailed completely out of the park!

What on earth was going on?