Its rather simple a time-loop or as same call a Infinite Loop rp(Basically refer to not completely serious fanfics I'd check out this guys time-loop/Infinite Loop fics for my vision
https://www.fanfiction.net/u/681915/Innortal) but there will be seriousness for awhile in such a rp till whoever are in the loops are ''awake'' in the loop system get tired of it and starts screwing around on matters or mind fucking people along with revenge among other things. Plus if we do it power levels, powers and abilitys even none native to the universe(in the case of a fused type of loop) or time period/person gets carried over to get more powerful, Of course physical strength wouldn't get carried over. There would be stuff odd in some loops for example a fused loop of harry potter verse with Anko deaged to a first year at a magical school and other characters from other series with varying changes of age or sex among other things. Plus the point of ''awaking '' or loop starting wouldn't be set it would be at different points when we feel like it