Ochre Star, Pisaster ochraceus
Masses of these stars used to be seen just below the surface all along the Pacific coast of Canada and the USA. But then the sea star wasting disease wiped a lot of them out starting in 2014. They are slowly making a return but they are still not in the numbers they used to be. They are referred to as Purple Ochre Stars even though there are occasionally orange coloured ones mixed in with them.