Candice Renoir (2013)

S2E12 Psych Out

While interring one of the time capsules that brought the Thundercats to Third Earth, the capsule unexpectedly shatters, releasing gases that continually de-age Lion-O. The rest of the Thundercats scramble to find a solution, discovering that the Cave of Time holds the key to reversing the effects. They must hurry to bring Lion-O there before he completely disappears. Matters take a turn for the worse when the younger Lion-O and Snarf are captured by the Lunataks, complicating their race against time.