Hallucinated Tiny Spider

Sitting in my recliner, I looked down on the left arm and saw movement. For a moment, I saw tiny eyes looking back up at me. A spider. Disappear! Just like that, it was gone. I looked all over, but couldn't find the arachnid at all. This is unlike the big black bulbous spiders I had been hallucinating. This one showed up clearly, then went away just as clearly.