So I was just digging through today's batch of pocket change and I found a 1975 penny with a huge star in front of Lincoln's face. I can't find any info online. Should I assume that it's some sort of novelty?
Novelties. Around the Bicentennial there were literally millions of such counterstamps applied to cents and sold as "souvenirs". I have seen all forms of US insignia, state symbols, and other shapes. The 1975 date is really telling as well.
A photo would help but based on your description someone counterstamped your coin for some reason. If you had a punch and a hammer you could counterstamp more coins.
you're right. Upon closer inspection of the back of the coin is slightly bowed out which is indicitive of being counterstamped.
