Time Travel

Time Travel is the ability to travel through time.

Overview
The user imagines their own inner universe and manipulates the particles and anti-particles generated in pairs by the user's intense cosmic rays. When the two types of subatomic particles, one moving forward and other backward in time, begin to imitate each other's movements, the user can travel backwards in time.

Garou
After achieving his Cosmic Fear Mode, Garou gained the ability to manipulate particles within his body on sub-atomic level and force them to behave like anti-particles. He refers to this power as the ultimate technique of "his fist". However, Garou stated that he has not mastered this technique for time travel. Despite this, it was implied that in the end, he managed to master this technique, as seen when Tareo was woken up by what seemed to be Garou's soul from the Ominous Future, which then slowly disappeared from sight, signifying that he traveled through time to say goodbye to the boy.

Saitama
After being defeated by Saitama, Garou passed on to him his time travel technique in hope that Saitama could learn and master it in order to change the Ominous Future that has happened during their fight. While executing his technique, Garou was soon killed by "God" who took back his powers in the process, although not before Saitama managed to replicate Garou's ability to time leap and use it to successfully travel to the past. Upon returning to the moment Garou was appearing in front of the heroes on Z-City, Saitama was able to defeat him with a single punch before any bad consequences could occur again, thus successfully changing the Ominous Future. However, right after this success, the "future" Saitama was forcibly pulled towards his "past" self in that timeline, causing them to merge and become one, with the now and only Saitama unable to remember what's happened.