A pre-cud Looks to be an earlier stage of either. RCD-1c-1952S-02R or RCD-1c-1952S-02R http://cuds-on-coins.com/lincoln-cent-1909-1958-rcd/
It's a worn example of a big die crack forming, and I agree with our esteemed reptilian colleague, @furryfrog02, it's likely to take out that whole section of the die if it stays in business long enough.