As a child, I would often become delirious when I had a fever, always while I was in bed for the night. The first time I experienced it, I was terrified because the giant robot spiders (from the episode of the original Spider-Man cartoon I had watched that day) were going to zap my mother.
Along with the dream sequences, my delirium usually included 3 uncomfortable sensations. First, there was the feeling of having a balloon in my throat (kind of like the piece of rubber stretched over your mouth when getting a filling at the dentist), choking me. Second, there was the sensation of wrapping myself around a sharp, thin wire (~1mm diameter), which at the same time was a concrete pillar (~2ft diameter). I don't know how else to put it. Third, there was always some task I had to do which would spin out of control. For example, I would have to sort or pack a bunch of balls, which kept multiplying and multiplying, making me despair that I would never finish the job. Sometimes there was just one ball (they were always yellow) which continued to expand, becoming bigger than the planet, the galaxy, even. Terrifying. These three sensations always felt as if they were building up, threatening to engulf me (how I feel sometimes when I have bad anxiety).
I haven't been delirious in years. In my teens, however, I began experiencing those sensations outside of the delirium. I could even feel them in various body parts, like my arm would be choking on a balloon. This is basically impossible to tell anyone without them thinking me mad (they may be right). It still happens to me, every once in a while.
Twice this past week, while trying to sleep I got the wire/concrete thing. It started in my torso, migrating then to my legs. The same engulfing panic ensued and I had to get up and do something to distract the feeling away.