/particle angryVillager ~ ~ ~ 0 0 0 1 20000000 force @p

This command causes the client to crash.
I know, that there has been a Bugreport before that has been closed, as this might not affect computers with much computing power. Anyway, using this command (or a similar one), a server owner is able to max out the memory consumption of a client's JVM instance which causes it to hang while only sending one packet. Crashing the client should be considered a "denial of service". That's why I think this should clearly be considered a bug and be fixed in future versions of the game.

I attached