Re:Heaven's design team 10 and 11 3 Months, 1 Week ago
ok found the episode:
the anime is about a research and development team in heaven who's jobs are to create the animals of earth at the dawn of time through funny trial and error.
Episode 10 was about one of them fascinated with aging. At the end of the episode they begin to study how aging works on a species. From the ones that do (no age just young and old dot like creatures), the kind that dont age (like lobsters) and consider ones that rejuvenate. They experiment on a horse but but it becomes a blob like a jellyfish. explanation is just structure.
They try to change the calculations with a halo on a creature they are working onbut its used too much. There is an explosion, one is unhamred but finds the older of the group young again. He wonders if the others were effected but dont see any of them. But goes to the conclusions they were blasted through a door to an enviroment. episode ends
so next week's episode probably is them looking for them in the enviroment when they are younger