Which organism is known for being a crawling eukaryote commonly found in water?

Amoeba is known for being a crawling eukaryote found in water due to its unique ability to change shape and move through a process called pseudopodia formation. Pseudopodia are temporary, foot-like extensions of the cell body that allow the amoeba to "crawl" along surfaces, making it adept at navigating its aquatic environment. This characteristic enables it to seek food, escape from threats, and adapt to its surroundings.

While other options include organisms that are also eukaryotic and present in aquatic environments, they exhibit different modes of movement. Paramecium uses cilia for locomotion, Euglena moves with a flagellum and exhibits photosynthesis, while Stentor is a filter feeder that primarily utilizes ciliary movement. These differences highlight why the amoeba is specifically recognized for its crawling capability among these organisms.