DDOS and buy?
More or less this. A pump and dump is
convince others something is worth more than it sells for | secretly sell them yours instead of buying along with them
The logical opposite would be
convince others something is worth less than it sells for | secretly buy theirs from them when they decide to sell
You recognize the former when you think someone is full of shit about how great something is; the latter when its about how worthless something is.
A DDoS can fit into this theme because maybe the chaos makes people think bitcoin is unstable, shady, forever destined to be targeted by more of this. It's profitable as long as the market corrects itself afterwards.