Bukkit

Mobspawner with custom thrown potions

First, create your potion and take it to first inventory slot
Remember the spawner coordinates (by F3)!

disable spawner:
block RequiredPlayerRange = 0

create spawn data:
block SpawnPotentials[0].Type = "ThrownPotion"
block SpawnPotentials[0].Weight = 10

put potion from your inventory to spawner:
block SpawnPotentials[0].Properties.Potion = inv [0]

Edit spawner as you need:
See this tutorial and MobSpawner format (minecraftwiki.net)

Spawn potion at location:
Move to this location and copy it
me Pos copy
next, paste it to spawner
block SpawnPotentials[0].Properties.Pos paste

Throw potion:
list copy
buffer [0] = 0 double (x)
buffer [1] = 0.8 double (y)
buffer [2] = 0 double (z)
block SpawnPotentials[0].Properties.Motion paste
Throw potion to vector x:y:z

update spawner:
block EntityId = this SpawnPotentials[0].Type
block SpawnData = this SpawnPotentials[0].Properties

Set enabled:
block RequiredPlayerRange = 16 (radius)