A first for me! Very excited.
This beautiful little guy or girl was just passing through on its way to warmer wintering grounds most likely. I have checked many times as have dozens of other interested birders but there have been no further sightings.
This is the same species of Owl which they recently saved from the Rockefeller Christmas tree:
https://www.cnn.com/2020/11/19/us/rockefeller-christmas-tree-owl-trnd/index.html

Armina californica was located in a submarine canyon on sandy substrate at a depth between 20-40 feet. Length was between 2-4 cm. Water temperature was 51 degrees F.

Note that this animal was found on Renilla koellikeri, a known food source.

9 mm long, found under a low intertidal cobble. Scanned from a 35 mm slide taken by Jim Lance of the single individual of this species I found at Santa Cruz de Miramar, Nayarit, Mexico.

The 2nd and 3rd images show the extensive boulder field at Santa Cruz de Miramar, where Jim Lance, Gale Sphon and I found a total of 15 species of heterobranch sea slugs on this date in 1985.

Orienthella sp. with eggs was located on reef wall at a depth of 10 feet. Length was not measured. Water temperature was 62 degrees F.

Note that this variation has an inconsistent white stripe on the dorsum and cephalic region, contrasting with O. trilineata that has a continuous stripe. Also note that O. cooperi may have inconsistent white stripe, but O. cooperi does not have annulate rhinophores.

This animal was located on reef at a depth of 60 feet. Length was 1 cm. Water temperature was 53 degrees F.

This animal appears to be D. davebehrensi. Oral tentacles were not observed indicating the genus Doriopsilla. The gill is white, as in D. davebehrensi, but the animal is more oblong and the rhinophores are longer than typically observed and the mantle skirt does not appear to extend laterally beyond the foot. Doriopsilla davebehrensi has the dispersal potential to reach the islands (Hoover et al, 2015). Bertsch (2019) reports that D. davebehrensi is rarely found at the islands and is common along the coast at Bahía de los Ángeles.

BERTSCH, H. 2019. Biodiversity and natural history of Nudipleura communities (Mollusca, Gastropoda) at Bahía de los Ángeles, Baja California, Mexico. A 30-year study. Geomare Zoológica, 1: 89-136.

HOOVER, C.A., LINDSAY, T., VALDÉS, Á., GODDARD, J.H.R. 2015. Seeing double: Pseudocryptic diversity in the Doriopsilla albopunctata – Doriopsilla gemela species complex of the north-eastern Pacific. Zoologica Scripta, 44(6): 612-631.

Found crawling on mud flats at low tide. Photo five shows defensive response when touched from behind: it flared its cerata and then buried itself. Videos of it cruising, digging, and burrowing here: https://flic.kr/s/aHsmJBURnQ

This animal was located on reef at a depth of 45 feet. Length was 1 cm. Water temperature was 53 degrees F.

The identification is uncertain. Ceratal cores are tan. The cerata project from the dorsum as a single protuberance and subsequently branch. These features closely resemble Apata pricei, but this animal lacks the subapical brown band found at the base of the cnidosac and A. pricei is not among the species observed previously in the Gulf of California (Bertsch & Aguilar-Rosas, 2016).

Bertsch, H., Aguilar-Rosas, L.E. 2016. Invertebrados Marinos del Noroeste de México. Universidad Autónoma de Baja California (A.C. Pasini ed.) Ensenada. 432 pp.

The image is of a pair of freckled dorid nudibranchs (Peltodoris lentiginosa) sitting on top of a population of cloud sponges (Aphrocallistes vastus) at a glass sponge reef.

P. lentiginosa is one of only two species of nudibranchs (the other being Doris odheri) that has been scientifically confirmed (specimen samples, gut contents & fecal contents analysis) to eat glass sponges in the northeast Pacific Ocean.

Even though glass sponges are abundant throughout the world's oceans, the only other record of a glass sponge predator comes from Antarctica from the 1970's.

http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7410.2012.00262.x/full

Images showing two of four individuals which showed up recently in the filter beds of the seawater system at UCSB's Marine Operations Facility. The water is pumped in from a depth of 55' off of Campus Point, and the nudibranchs were likely pumped in as larvae.