I don't know why people aren't noticing this but as of now it is impossible to put custom mobs into multiplayer. Why do you think mo'creatures, more creeps, aether, and other mods like that are only in singleplayer.
@humblepie6 There are still some in Java, just the Vietnamese subspecies was lost. The Javan population is actually pretty stable and they are breeding so there is still hope for them. The problem now is there isn't really enough space for the population to grow in a safe place.
I didn't think the Vietnamese Rhinos would survive, even if they beat the poachers there was still too few and inbreeding would get them instead. At least the Javan Rhinos in Java have a stable and maybe even growing population. Oh ya, the guys who are all hating the Vietnamese and China and what...
I don't know why people aren't noticing this but as of now it is impossible to put custom mobs into multiplayer. Why do you think mo'creatures, more creeps, aether, and other mods like that are only in singleplayer.