Viruses that attack bacteria are called bacteriophages. They come in a variety of shapes, but some common ones include:

* Icosahedral: This is a shape with 20 triangular faces, like a soccer ball. Many bacteriophages have this shape.

* Filamentous: This shape is long and thin, like a filament.

* Head-and-tail: This is a complex shape with a head containing the genetic material and a tail used to attach to the bacteria.

Here are some examples of bacteriophage shapes:

* T4 bacteriophage: This is a classic example of a head-and-tail bacteriophage.

* M13 bacteriophage: This is a filamentous bacteriophage.

* MS2 bacteriophage: This is an icosahedral bacteriophage.

The shape of a bacteriophage is important because it affects how it interacts with its host bacterium. For example, the tail of a head-and-tail bacteriophage allows it to attach to the surface of the bacterium and inject its genetic material.