I just moved into a new house and have a couple of these in the back yard. Not sure if it is a weed or an ornamental.
Anyone recognize it?
Bay Area, CA (usda zone 9a/b)
It's an ornamental, Acanthus, or Acanthus mollis. Its fancy shaped leaves look so familiar because this plant is the prototype for the stylized "foliage" that you see in classical artwork & sculptures, like when the artists wanted to decorate column tops or other architecture or make a background for some kind of inscription. Be careful, though. Those flowers are very sharp inside.
It is, as already said, Acanthus mollis, an herbaceous perennial plant - in your area, it may be considered invasive. Whether you like it or not is the consideration for deciding whether its a 'weed', but it is difficult to get rid of, and it does spread over time by means of underground, deep roots. If you want to get rid of it, deep digging is required, as well as persistence - it may resprout for the following two or three years if there's any root left behind. Each flower on the stalk has 4 sepals and one spiny bract, but the leaves on A. mollis are soft to the touch. Tolerates shade, but flowers better in sun, and drought tolerant, more information here https://www.pacifichorticulture.org/articles/wildly-successful-iacanthus-mollisi/