<ul data-eligibleForWebStory="true">Deep reinforcement learning (DRL) has been successful in various domains, but it is susceptible to backdoor attacks during training.Existing backdoor attacks in DRL often use simplistic trigger configurations.A new framework called TooBadRL focuses on optimizing DRL backdoor triggers in terms of timing, spatial dimensions, and magnitude.TooBadRL introduces an adaptive freezing mechanism for injection timing and a cooperative game approach to select influential state variables.Furthermore, TooBadRL utilizes a gradient-based adversarial method to optimize injection magnitude under environment constraints.Evaluation on three DRL algorithms and nine tasks shows that TooBadRL increases attack success rates while maintaining normal task performance.This research emphasizes the significance of systematic trigger optimization in DRL backdoor attacks.The TooBadRL framework's source code is available at https://github.com/S3IC-Lab/TooBadRL.