Many organisms possess eyespots, but the most commonly known and easily recognizable example is the Euglena.

Here's why:

* Euglena: This single-celled protist has a distinct red eyespot called a stigma. It's located near the base of the flagellum and helps the Euglena detect light for movement towards it (phototaxis).

While Euglena is a great example, you'll find eyespots in various other organisms, including:

* Other algae: Many algae species have eyespots to aid in light detection.

* Planarian flatworms: These worms have eyespots that allow them to detect light and dark.

* Some larvae: Some insect larvae, like the larvae of some moths and flies, have eyespots.

It's important to note that the complexity and function of eyespots can vary significantly between different organisms.