The Ultimate Thrice Cream, officially known as Chunky Lala-Choco-Nina-Nana-Bana Berry Swirl (with nuts), is a delicious jewel-encrusted thrice cream treat that's swirled with various flavors. It's only seen or mentioned in "The Apprentice Games".
The Ultimate Thrice Cream was initially kept a secret from Chowder, but Mung finally decided to offer it to him as a bribe/reward for him winning the Apprentice Games. This, however, did not happen.
The actual winners, Pate and Ceviche, refused to accept the medal awards due to the poor sportsmanship on everyone else's part. When they left the medals behind, the masters began fighting over them while Chowder snatched them for himself, planning to use them to buy himself the Ultimate Thrice Cream.