I made a major DM goof last night during a Pathfinder session. What was supposed to be a relatively difficult combat to introduce the PCs to a hostile environment turned in to a massive ROFLstomp. First action first turn the wizard hits the Giant, Advanced, Mantis with Colour Spray. Stunned for two turns, which is enough time for the party to obliterate it, since it is flat footed, and the sorcerer uses several touch attacks on it. It doesn't even have time to register what's going on before it's pulped.
One thing in it's stat block stuck with me today, "Immune to mind-affecting effects". How, I wonder, can you tell what's mind affecting. So I pull up Colour Spray and take a look. Oh hey, right there in the top line "Mind-affecting"...........................................
Instead of a session of thrilling heroics, I got a wiffle, all because I was too lazy last night to read the whole god damned entry for Colour spray. Never Again.
Sounds like an Arrowflight game I was in once.
One of the PCs had been kidnapped in the night (and was now acting as DM, while the previous DM played a new PC) and another PC, though mostly a pacifist, was wearing his fancy armor and carrying his fancy runic sword. At some point, we're walking through town, and someone mistakes this PC for the one who got kidnapped, and gives him this "mark of death" sort of thing, meaning he's been targeted by this group of supposedly powerful assassins called the Jo'Jai.
Later, we're flying an airship through town and suddenly we get boarded by mercenaries. As everyone is fighting, the Pacifist separates from the group in order to steer the ship away from a cliff face. That's when a Jo'Jai assassin jumps from the rigging and flashes his weapon in a battle stance.
Of course, the Pacifist tries to think of a way out of the situation that doesn't involve violence, and rolls a Diplomacy (or the Arrowflight equivalent) check. It fails, so initiative is rolled. The Jo'Jai completely fails the initiative roll. The Pacifist makes an attack roll. Crit. The runic weapon does enough damage on that crit to kill the Jo'Jai in one hit.
Instant Replay: Supposedly scary powerful assassin jumps down in front of this pacifist guy and prepares for battle. Guy says, "I don't suppose we could come to some agree- Ah, sod it!" and makes one swing, cleaving the assassin in half, and sending him flying off the deck of the airship.
This lead to us constantly brushing off comments that the Jo'Jai were super powerful. "They're not so tough; This guy killed one without a scratch!"
Later in the campaign, a few of us were in a bar, and we got a tip that we were going to be attacked, and we should sneak out the back. Cue a 7' tall lizard, a 4' tall but bright green frog, and a dude in giant plate mail trying to sneak out a tiny window. Of course, we all fail, but guess who crit fails their Awareness check? The Jo'Jai assassins on the roof, about to drop in on the bar we were sneaking out of. The assassins look over, see us sneaking out, go "shhhh," and continue to sneak into the bar.
The DM was noticeably embarrassed.