The Horror of Hook Mountain is an episode from ThunderCats Roar, which originally aired on March 21, 2020.
Official Summary[]
Tygra takes Lion-O climbing up the peak of Hook Mountain to teach him a lesson about trust. But when they get trapped by a snowstorm and take refuge in a creepy cabin owned by the creepy Snowman - it's Tygra's ability to the trust that's gonna be tested.