In creative when even one snowman fights with a skeleton, sometimes game hangs for good and there can be seen an arrow in mid air turned tip to skeleton.

I guess it's snowball colliding with skeleton's arrow mid-air.

It hangs indefinitely.

Edit:
Can't confirm now, it was on my niece's computer, but can confirm it happened 5 times consecutive. Let's keep it open, I'll post more when I get back on that machine.

Edit:
The screenshot I attached earlier shows moment when it hung. It's not a random screenshot, if it may look like so.