Game Breaker Spells - What are they?

[JDJblatherings]

There is a great defense versus Fly spelled atatck squads...dungeons.

 

[Slife]

True Seeing does totally scrap any plots about polymorphed or shapeshifted creatures, and renders all illusions pointless.

Well, it looks like the villain has protected his castle with an invisible guards and wards spell. Because of the obscuring mists, you can't see a thing.

Oh, you dispelled/Gust of winded it, did you? The magic trap with see invisibility now can see you. Roll a reflex save.

 

[DandD]

I don't get it. What traps, guards and ward spells are coming into effect when you use True Seeing and/or Gust of winds?