Unintended Exploit with Ars Nouveau (Possibly other mods)

[LifeHckr]

Using the starfish trinket while using a self -> harm (Or any other damage type) spell from Ars Nouveau causes the xp gain on enemy hit to proc, allowing for infinite xp to be gained.

[BlueAgent]

Probably fun to leave in. :P
Even if preventing self inflicted damage from giving exp you could do something similar with two players.
Even if limiting it to damaging non-players, you can still just make a mob farm and hit the mobs.

[NielsPilgaard]

This exploit is also possible with the Target Dummy from the MmmMmmMmmMmm mod, that might be a bit too strong 😄