Pseudo-Hair
This particular creature is waiting for us on the first planet we find whose life has a common ancestor with ours (so if panspermia isn’t real, don’t worry about it). It’s an… interesting parasite: as you might guess, it infests a human’s hair follicles, effectively replacing a host’s hair. The effect looks rather like normal human hair, except for the random wild color shifts and the way that Pseudo-Hair moves independently. You can cut Pseudo-Hair without pain… to yourself; the organism itself doesn’t like it very much, although it won’t take lasting harm unless you do the equivalent of a depilatory.