Known bug in 0.9.15 - was fixed a couple of days after release, so will be in (hopefully very soon) 0.9.16, and has been reported, oh, 4 or 5 times in the interim.

Whether it happens or not kind of depends on whether your system clears memory before allocation. Wasn't discovered on my linux system since the allocated pointer was being set to cleared memory.
Upshot, silly accident, not everyone crashes, don't do that until it is fixed.

BTW, there is another bug in hedgehog death in 0.9.15 - unfortunately the drowning bubbles were being set even after the hedgehog disappeared and the memory was released. This causes a small chance of a crash. This can only be completely avoided in 0.9.15 for now by doing your own build or by playing a theme with opaque water (the mud on Compost or goo on Underwater - those themes also move to next turn faster since there is no drowning animation)

Thanks for the info. I just now noticed that there is a bug tracker.