I have never scrubbed my arm pits with a toothbrush

Spark is in the bathroom getting ready to  brush his teeth before bed.  He come charging out of the bathroom waving his toothbrush over his head and yells, "Who has been scrubbing their arm pits with my toothbrush!"  He was serious about this.  So I go in there, take off my glasses because I can't see up close with them on, and size up the offending hair.  I don't see anything.  He points out this little, teeny, tiny hair stuck in the bristles.  No arm pit hair, I think it was from the dog.  Whew!  Disaster avoided.