Need to Know what we saw

July 8, 1999
From: Eileen Steger

I was vacationing in Capitola, California over the July 4th long weekend. On the beach there was a lot of seaweed and also this sea creature I have never ever seen before.It was black and as big as a football I would estimate. When we tried to push it back in it put out some purple ink. Also its head emerged and these antenna looking things came out. I have never ever seen this before and want to know what it is. Is is harmless. Would it sting like a jelly fish if you
stepped on it.

Again, it was black and the size of a football and it was just this big fat blob of stuff and it was with a lot of seaweed.

Thank you in advance for any info you may have.
PS. We saw two of them on two different days. Another person saw four of them


Dear Eileen,
Your animal sounds like a Sea Hare. Your animal is probably Aplysia vaccaria which is found in California, is often black, and can grow up to about 1 meter long! I'm sorry I haven't a photo of it but there are photos of other species of Sea Hare in the Forum which you can find if you look in the Sea Hare Species List.

Many Sea Hares produce purple ink when they are squashed or irritated. Sea Hares feed on sea weeds. Some live on rocky coasts and others on sand or mud in quiet bays and inlets where there is not much water movement. Sometimes you find them washed up on beaches as you have done. This usually means they are dying or have been washed in from deeper water after storms.

There is a lot of information on Sea Hares in the Sea Slug Forum. If you go to General Topics Page and go down the list until you reach Sea Hares you will find quite a few pages with interesting stuff on animals like your 'black football'.

They are not dangerous.

Best wishes,
Bill Rudman.

Rudman, W.B., 1999 (Jul 8). Comment on Need to Know what we saw by Eileen Steger. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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