This is Anthopleura artemisia, sometimes called the Moonglow Anemone.
We looked around and found a few more individuals, but true to form, they were all quite different from one another. Although books often describe how variable this species can be, I have yet to find an explanation of why this anemone comes in so many different and striking color patterns.
Below is another version of Anthopleura artemisia. Note the mottled tentacles.
And here's another wonderful example:
If you're interested in finding this anemone, look for it in intertidal areas attached to rocks that are buried by sand and shell debris.
It's a special day when you can look down and be captivated by the oral disc pattern of Anthopleura artemisia!