It'd be nice if there was a docked entity limiter in the config file for this kind of thing. We have a docked Entity Chain Limit but no overall docked Entity Limit.
Config Limit On Chains, Singles (AKA chain heads), and global would help. Having a chain start limit be separate from the global limit would help too.
Docked Entity Chain Limit: ???? : Already in game
Docked Entity Chain Start: ???? : How many heads of chains of docked entities?
Global Docked Entity Count Limit: ????? How many entities in total including those in chains?
For Chain start it doesn't care how many are in the chain, while global does. The reason for having it like this is so you can limit things a little better without killing other things at the same time.
That said, a bricknaught?????
Also they're doing it wrong if they want to crash a server. There are people here you could perma kill servers in way less blocks. XD