Looks like it is, definitely different enough from wasabi to not be wasabi (even though it’s the same family of plant).

Not sure about seeing floaters before migraines, but what you see could be migraine auras. I have them and they affect my field of vision prior to a migraine. I’ll see flashy/persistent “dots” or completely be unable to focus on certain things, like I have a blind spot. Hate it, but it at least gives me time to grab meds before the pain sets in. Usually happens ~20-60 minutes before onset.