Our Damaged Garden Investigation

So... we have an issue over here in our garden at Our Sound Home. It's a weird one, so stick with me, folks.  The other day I was out in the garden, looking around at our progress. I try and get out every other day to at least check out how our plants are doing. I'm learning things can change pretty quickly in the garden during the spring season!
So, on my walk around our yard earlier this week, I saw that an area of the garden closest to the water was damaged. My tulips were totally torn up, squashed, and the area was just really messy. What the heck?! Kyle and I were thinking maybe it was a dog, or possibly a raccoon? It didn't look like anything was dug up, it was mostly just torn a part:

I was really bummed out, because these were tulips I had planted and as a first time gardener; I was annoyed that my work was ruined! Fast forward a few days, and it happens again! Only this time, it looks so much worse:

I hate to go into the messy details, but just because I really want to hear your thoughts on this, I am going to get into the gross part. There was vomit on the ground - in the grass, patio and garden bed - that had shells and bits of crab legs. Not like a little bit from a bird, but something much bigger.

The shape of the area that is damaged, the accessibility to our yard off our bulk head, and the messy gross stuff that was left behind are leading us to believe it's a seal or sea lion. Only, I thought they were more fish eaters than shellfish eaters. Do you have any other guesses?

We're tempted to get a camera and motion light to see if we can capture it on camera, because right now our suspicions are just a hunch. But, we're also trying to figure out how to keep whatever it is out of our yard in the future. I think our best idea as a short term solution is getting a few inexpensive solar lights to line the garden bed. Maybe the light at night will keep it way? We're also doing some research on the Washington Department of Wish and Wildlife website to see if we can narrow it down. I am super curious what you think. Let me know!