The death of a chronic alcoholic is being described, including the delusion that insects are crawling on him.
The technical word for this is formication.
Big difference between an "m" and an "n".

Given the choice between m and n as a way to go...

Ps What is the difference between illusion, delusion and hallucination?

Everybody occasionally has illusions, a misinterpretation of some sight or sound. A delusion is a product of disordered thinking, such as thinking people are saying bad things about you, when they are not even talking about you.Or thinking that you are Napoleon, etc.
I just remembered, a while back we had a thread about the illusion of the moon looking larger when it is close to horizon than it does when overhead.
A hallucination is typically hearing or seeing things that are not there, due to some form of mental illness. Of course all the diagnostic terms have changed since I retired almost thirty years ago.

A hallucination is typically hearing or seeing things that are not there, due to some form of mental illness.

not just to some form of mental illness-- many migrain suffer's have small hallucinations-- visual images, sparks of light that 'aren't there' -- and there are also drug induced hallucinations

And, wwh, I agree with your distinctions. I would add that if you fine-tuned the difference between hallucinations and delusions, the former would be things that one believed to exist outside of one's consciousness, such as strange beings (or dogs) speaking to oneself, and the latter (i.e., delusions) would be internal beliefs that have nothing to do with outside reality. That is, if we could ever agree about what reality is.

I think we're saying the same thing, but I just wanted to say it in a different way to satisfy myself on this somewhat mellow Friday evening.

Dear of troy: I was trying to keep it short. LSD can cause mental aberrations. Remember Art Linkletter's daughter taking acid that then making swan dive out the window?
Or my daughter seeing things that weren't there when very sick with measles. Speaking of LSD, I remember patient who defended his use of LSD by saying:"The government is spending millions to put men on the moon. I can go out of this world for a buck." It really messed up his life.