First high-res look at microbial ballistics: Harpoons, spears, Gatling guns

They actually get smaller yet - cellular warfare even. Entire protein collections (R-Bodies) that are like explosive coiled springs [1] that can be made to be pH-sensitive so that when they're 'eaten' by a cell, they explode, bursting the cell from the inside.

Bacteriophages have terrifying-looking injection ports [2]. And there are other viral 'latch-like' proteins that do significant damage to host membranes when deployed in order to permit their own payloads to be deposited.

The entire CRISPR system is a defensive homing weapon used to literally dice up a virus's DNA were any of the above weapons successfully used to enter a cell.

[1] http://pubs.acs.org/doi/full/10.1021/acssynbio.5b00237

[2] https://en.wikipedia.org/wiki/Bacteriophage