The Invisibility Cloak is a special cloak created by Zach Varmitech that allows the wearer to turn invisible. Zach created it in "Back in Creature Time," where he learned that Aviva had created a time machine in the form of the Time Trampoline and decided to test out his new Invisibility Cloak by sneaking into the Tortuga to steal the Time Trampoline and trap the Wild Kratts in the past. Zach successfully managed to invade the Tortuga, but the Wild Kratts managed to foil his plans and he was left to retreat.
The Invisibility Cloak reappeared in the Halloween special, "Creepy Creatures!". Zach once again used it to infiltrate the Tortuga, where he stole the Miniaturizer. Zach nearly made a clean getaway, but Martin in his Goliath Birdeater Power Suit, detected a threat and shot urticating hairs, causing them to get stuck to Zach and reveal his presence. Zach the tried to flee, but he got caught and had his Zachbot retrieve him, leaving the Invisibility Cloak behind. When Aviva notified Zach of this, Zach simply declared it a trade as he made off with the Miniaturizer. It is unknown if Zach ever got the Invisibility Cloak back. This was changed in the episode "The Vanishing Stingray," when Zach complains that his Invisibility Cloak doesn't work when touching water. This also implies that Aviva gave back Zach's Invisibility Cloak back.