I have some items which fire Fireballs, which mostly works, but when travelling, the fireballs movement goes... rather intresting.
For the first second or so, it flies as expectd, only to then appear somewere way further(but still in correct direction, just alot further).
In the case of ghast fireballs, they seem to duplicate, with the "ghost" having its aim a bit off (only the original one seems to impact).
Code:
https://github.com/Wuerfel21/The-Derpy-Shiz-Mod/blob/master/src/main/java/net/wuerfel21/derpyshiz/items/FireSword.java#L65-L84
https://github.com/Wuerfel21/The-Derpy-Shiz-Mod/blob/master/src/main/java/net/wuerfel21/derpyshiz/items/ItemFirechargeLauncher.java#L31-L45