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AckStacks are a group consisting of five yellow Acks who stand atop each other like a tower. These enemies appear in Donkey Kong Country Returns and Donkey Kong Country Returns 3D. AckStacks are a type of Toothberries.
If Donkey Kong and Diddy too close to an AckStacks, the Acks lean back and fall with their mouths open. Sometimes AckStacks take up entire space from collapsing and may knock the Kongs down an abyss. Donkey Kong can dodge an AckStack from jumping back, which causes every Ack to land separately, with their fangs stuck in the floor. These Acks are vulnerable to jump attacks. Unlike normal Acks, the Kongs can defeat them with a single hit. The Kong Roll is ineffective against AckStacks, but the Kongs are not injured from attempting this maneuver.