Answer:
Flow
Explanation:
In psychological term, Flow refers to a situation when our brain reach optimal state of focus that massively optimize our capability to perform a certain task. When this happen, our brain tend to ignore our surrounding and our attention is completely focus on one single thing that we're working on.
Example for this would be a writer who so immerse in her fantasy to the point where she write her story for 20-hours straight, forgetting the fact that she hasn't eat for the whole day.