Tonton Streaming ThunderCats (1985) S1E7 - Trouble with Time

With their supply of Thundrillium running low, the Thundercats set off in search of a fresh supply. Tygra detects a large deposit in a cave and goes to investigate - unfortunately, he has entered the Cave of Time and anyone who ventures in there will age rapidly until they die. His only hope is that Cheetara's speed will be fast enough to allow her to escape the Cave's effects.