Water molecules attract each other. Typically molecules are surrounded by other molecules and feel attractive forces from all directions. So they tend to clump together. The effect is especially pronounced for molecules at the surface, since there aren't any molecules attracting from beyond the surface. That creates a net inward force, that contracts the blob and acts like kind of a skin. It's 'surface tension' and it's why tiny insects can walk on the surface of pools of water here on Earth.
Here's a video in which they make bigger blobs of water and then put a camera inside a blob (no idea why). Later they show how the water is kind of sticky
this is the essence of wetness and capillary action, and how it wants to adhere to surfaces and to the astronauts hands. So they can wet their hands on opposite sides of a blob and then pull their hands apart, stretching the blob.
https://www.youtube.com/watch?v=g_HEsZJrluE