This is most likely conjugation. As we know, bacteria multiplies asexually using binary fission. Basically, bacteria divide themselves and reproduce without needing a mate. Reproducing asexually is beneficial because less genetic mistakes are made, but it has its downsides too. If a group of bacteria has the same genetic composition, and there’s a disease that affects one bacterium, then all others will be wiped out as well, for they lack genetic variation.
Anyway, bacteria found a way to overcome this and reproduce asexually AND asexually. This means they can reproduce by themselves, but they can also somewhat reproduce with others through a process known as conjugation. Do not confuse this, though— conjugation is merely the exchange of DNA between two bacteria. There is no third party being produced.
A donor bacteria will insert a pilus into a recipient bacteria, and share the DNA. This creates genetic variation in a population of bacteria by jumbling up genetic material between two bacteria.
Hope this helped a little :)
