The spell's name was Sedated Perception.
It was a four-star F-Rank spell belonging to the time element!
This was the same spell Linda had in her arsenal. Of course, hers was an E-Rank one.
Sedated Perception was one of the most common spells among the time element rankers. And also one of the most hated ones at that. Because it largely contributed to the time-element rankers having to go through frequent bouts of uncalled-for time dilation.
Of course, Eren was worried about the side effects of using the spell as well. But he thought he should give it a try since his time element affinity would at least get utilized this way.
The self-casting spell's effect was simple. It affected the user's perception of time. When the spell activates, the user would experience a slow passage of time around him.