Hey, thanks for sharing this.
First I listened to the song by itself and thought, it's chill and a little dreamy. I didn't pay much attention to the words.
Then I listened and watched the video. I usually think music videos don't add much to a song, but she did a good job (she directed, apparently) with the simplicity of the image. The snake was impressive and when it envelops her, it's freaky (and also a little sexy, I have to admit). In this case the video enhances the song, which I might otherwise ignore as coffeehouse background music, not that it's bad, just not super memorable. The opening drone shot is pretty cool.
I looked up the lyrics. The song is about a man who takes advantage of an underage girl and has a hold on her because she initially looked up to him as a role model. Obviously the constrictor represents the predator/abuser. It appears both docile (almost loving) but dangerous and very much in control. Of course a listener can project his/her own experiences onto this to an extent, but the lyrics seem pretty obvious ("And you swear you didn't know (didn't know) / You said you thought she was your age").
Obviously snakes carry a long history of symbolism as demonic or evil, but she gave the anaconda the respect it deserves and didn't treat it as anything other than what it is. It is a beautiful animal that will not hesitate to fukk you up.
Side note, it's nice to see Billy Eilish doesn't thin out her eyebrows. I haven't seen that since the days of young Brooke Shields and Madonna. Never understood why women do that, unless they have a unibrow or something. Though I'm sure Billie isn't worried what I think.