Amplification attacks generate an enormous flood of unwanted traffic towards a victim and are generated with the help of open, unsecured services, to which an adversary sends spoofed service requests that trigger large answer volumes to a victim. However, the actual execution of the packet flood is only one of the activities necessary for a successful attack. Adversaries need, for example, to develop attack tools, select open services to abuse, test them, and adapt the attacks if necessary, each of which can be implemented in myriad ways. Thus, to understand the entire ecosystem and how adversaries work, we need to look at the entire chain of activities.This paper analyzes adversarial techniques, tactics, and procedures (TTPs) based on 549 honeypots deployed in 5 clouds that were rallied to participate in 13,479 attacks. Using a traffic shaping approach to prevent meaningful participation in DDoS activities while allowing short bursts of adversarial testing, we find that adversaries actively test for plausibility, packet loss, and amplification benefits of these servers, and show evidence of a "memory" of previously exploited servers among attackers. In practice, we demonstrate that even for commonplace amplification attacks, adversaries exhibit differences in how they work. CCS CONCEPTS• Security and privacy → Denial-of-service attacks.