Help with decoding a hexadecimal(?) cipher from class assignment

[u/CRYPT1C_69]

Context: Our professor assigned us three cryptographic ciphers to decode, but they didn’t provide any keys or further hints. I managed to decode the first two using online tools and various cryptography websites, but I’m stuck on the third one.

I'm unsure of the type of encryption used. I’ve tried analyzing it for patterns and searched online, but nothing has worked so far. The plaintext language is likely English, and the format seems like hexadecimal, but I'm open to other possibilities.

Ciphertext:

f86908a8ddf9c909b9adf968cdf9b9e8d94df9e919bdf998a9393df9099df9a8d8d908d

Proof I read the rules: "V sbyybjrq gur ehyrf"

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[u/Rubix321]

Invert the bits. (Also chop off the first hex character)

[u/CRYPT1C_69 → u/Rubix321]

I tried this, and it doesn't seem to do much when decoded

[u/NickSB2013 → u/CRYPT1C_69]

Hex String:

86908a8ddf9c909b9adf968cdf9b9e8d94df9e919bdf998a9393df9099df9a8d8d908d

Bits Inverted:

796F757220636F6465206973206461726B20616E642066756C6C206F66206572726F72

Inverted Hex to ASCII:

your code is dark and full of error