I wrote a little poem about a snake. The last verse reveals that the snake had eaten itself during a particular night. A night I am describing before.
"I ate myself - at that night"
I really like the number of words, their sound and the context, referring to that night. But I have doubts: is that good English? Is there a better way?
...
The sirens are singing
The tail speaks to me
Try, try, try, try me
I devour the life
Full of Lust and delight
I ate myself
At that night
The correct phrase would be "On that night".
Ngram for on/at/in:
"At that night" and "In that night" are both incorrect for the usage you are looking for.
If you look at the uses for "in that night" you will see that they are all different constructions to the one you want: https://www.google.com/search?q=%22in%20that%20night%22&tbm=bks&lr=lang_en
"At that night" is incorrect for referring to a specific night. The small amount of results on the ngram are due to phrases such as "at that night club" which is referencing a club not a specific night.
I think both 'in' and 'on' is wrong over here. Grammatically it would be 'I ate myself that night'. However, if you want the rhythm of your poem to keep going you can say 'That (any adjective describing night) night'
For example, 'I ate myself, That luminous night'. I think this would be the best option!
