This is a model of a bacteriophage for display purposes. It probably isn't super accurate but it makes for a nice display.

What is a bacteriophage?
A bacteriophage is a type of virus that can infect bacteria and archaea. In their “head” they contain DNA which inject into the bacteria they are trying to infect. 

In todays world, with many bacteria becoming resistant to antibiotics, bacteriophages may become a viable alternative.