A teardrop tattoo beneath the eye has symbolic, often context dependent meaning. One of which, a trophy signifying that the wearer has killed another human; the number of tears represents the number of victims. I think the CRISPR region, now famous for its power in gene editing and talk of designer babies, is the microbial analog of the infamous war trophy: tattooed tears.
Next to protists, viruses are a bacteria's worst nightmare. Viruses that only attack and infect bacteria, bacteriophages, are estimated to knock out > 40% of bacteria in the ocean. Clustered Regularly Inter-spaced Short Palindromic Repeats (CRISPR) is a segment of bacterial* DNA that provides them some immunity against viral attacks. How does it work?
When bacteria is attacked a virus, the bacteria is usually destroyed. However, those that survive the attack keep a piece of the defeated virus (Trophy) in its genome just in case it encountered that virus again; It would know how to defeat it again, like a vaccine.
In the genome of most bacteria you will find an area for war Trophy storage called the CRISPR region. There are 13 war trophies in S. thermophilus' CRISPR region.
*CRISPRs have also been observed in archaea.