<ul data-eligibleForWebStory="true">Decentralized cooperative multi-armed bandits involve agents aiming to minimize regret by exchanging information to select arms.Cooperative agents outperform single agents in selecting arms independently.The study focuses on recovering behavior in the presence of Byzantine agents who can provide incorrect information.The framework can model attackers in networks, offensive content instigators, or financial manipulators.A decentralized resilient upper confidence bound (UCB) algorithm is developed to handle Byzantine agents.The algorithm mixes information among agents and trims inconsistent extreme values.The normal agent's performance matches UCB1 algorithm for regret, surpassing non-cooperative cases.Each agent needs at least 3f+1 neighbors, where f is the maximum Byzantine agents in each agent's neighborhood.Extensions to time-varying graphs and minimax lower bounds for achievable regret are established.Experiments support the framework's effectiveness in practical applications.