I had real trouble with the crawler, I can't remember why I didn't use aeons as a shield (maybe I tried and it didn't work, more likely I was a dope and didn't think of it).
What I eventually did was:
I actually left the negator alive for most of the fight, then I used 'reflex' and 'jinx' (don't know if jinx did much) to stop gatling gun hitting much, and used 'pray' to heal what little damage I took. I slowly brought him down to under 5000 (I was paranoid so it was under 2000 I think) and hit him very hard with thor's hammer. This is a [censored] way of doing it and took forever, but it is fairly safe.