Residents in Silver Spring Township, Cumberland County thought they heard gunfire, but it was the sound of homemade explosive devices called "bottle bombs."
The prank devices can be lethal, and have put the area on high alert.
"To be honest, I really didn't know what to think," Silver Spring resident Jamal Smith said.
Over the past two weeks, a series of explosions were reported near the south end of Route 11.
Smith said that when he heard the booms, he rushed his family inside and feared the worst.
"We thought it was a gunshot," Smith said.
In certain cases, it might as well be.
Sealed into plastic or glass bottles, a volatile concoction of household ingredients is made to explode with force. The crime is well documented on YouTube, where wanna-be pranksters set themselves up to loose a finger - or worse.
"This could do some serious damage and to me, that's not a prank," said resident Stewart Beshore.
Beshore is concerned by the fact that if one of the bottles would fail to blow, it might be left for a passerby to find. Their unsuspecting touch could trigger a shower of burning liquid and shrapnel.
How's that for a funny prank?
"When I was in middle school, high school, our pranks were like a "wet Willie" or something like that, but these days it seems like the pranks are more on the serious side," Smith said.
Authorities said people should be cautious about picking up bottles when an area is being targeted. The homemade bombs can look like leftover soda at the bottom of the bottle.
If a bottle looks suspicious or the plastic seems stretched or distorted, call police.