In a narrative reminiscent of a Halloween tale, a company's migration from Hetzner's bare-metal infrastructure to AWS cloud services for their continuous integration (CI) pipeline is depicted as a journey fraught with challenges but ultimately rewarding. The transition, driven by increasing security and compliance needs, initially led to significant cost spikes and inefficiencies due to the incompatibility of their existing workflows with the cloud environment. With a baseline cost of $30k at Hetzner, the move to AWS resulted in an initial bill of $150k, escalating to $400k due to expanded scope, increased compliance requirements, and inefficiencies like cold starts and cache misses. The team overcame these hurdles by optimizing their CI processes, such as mapping critical paths, re-engineering caching, and right-sizing compute resources, which resulted in a 50% cost reduction and improved performance. Ultimately, the company achieved a stable, efficient, and cost-effective CI system that met modern compliance standards, though at a higher expense than their original setup, marking a successful adaptation to the cloud environment.