Summoned a mud mephit, which then summoned another mud mephit. Maybe we will get the "oops, is that a gate?" wild surge from BG2 eventually. Still remember that one.

Please don't. I would rather have negative effects that do not lead to instant reload and can be mitigated with strategic play. There is a huge difference between summoning a mephit (or even casting a fireball, though the current setting on fire is a better idea) and summoning a powerful creature such as a nabasu by a low level party.