We experience the weird and wonderful realm of...underground space dimensions? in episode 24 "No Questions Please" or "Break Through! AtlurKabuterimon"

Along the way: Izzy never actually wanted to find Tai, ravenous piles of pink poop, Tentomon being a sarcastic asshole to his oblivious partner, tentacle aliens that will send you directly to actual Hell, alphabet yoga, butt rockets, Ken tweeting about his insecurities to his only two friends, and Izzy is entirely devoured by his partner before the episode finishes.