The making of Seeing is Believing., step by step...

Recreated the rest of the eye. Then warped it and applied a plastic wrap filter.

Took a nail and liquified it into numerous tentacles.

Lots of hue/sat. I created the water surface by:
Render/clouds, filter/plastic wrap, free transform for perspective. Then played around with hue/sat again.

Used a brush for the bubbles.

Decided just now that the image wasn't very dramatic so thought I'd add a bit of drama and made a killer tentacle from the girl's forehead.

Used the texture of the chair for the squid tentacle.