Yea that's a fairly advanced pellicle. Honestly I just noticed the second picture in the original post. Didn't see that before...I would've thought that was a little more suspicious than the first.
I'd dump that one and clean everything that touched that beer very very well. Some people would tell you toss anything plastic that beer touched. I think that's overkill but I would swish some bleach water around in that fermenter then flush with HOT water prior to PBW soak then starsan.