I used to work at a Game/Hobby shop in Anchorage (sometime around 2012) where we would hold weekly Encounter games (this particular game was 4e). One day my PC says that the pre-generated characters who used the point buy system sucked. His gnome wiz or sorc (cant remember) could not kill anything that wasn't a minion.

I tell him he just needs to play to his characters strengths (not his STR stat) he keeps going on and on the entire 2 hours, really pissing off the rest of the table. Final I look at Peter the senior Game Master of the store and say, "he is pissing off the group, I don't want to throw him out or anything but I want to teach this guy a lesson" So I give him the next weeks encounter pages and tell Peter "I'm playing his character and he's going to DM for me.

Next Thursday rolls around and he shows up all smug and shit, tells the table that this is the mini boss before the BBEG, but this session has an instant kill trigger and for us to be afraid of it.

I look over his character sheet and yeah he's no power house character but he's not as bad as this guy been playing him. Just your typical spells honestly nothing great even his daily spells we meh at best.

As we play I keep telling myself all I have to do is prove a point, either kill at least 1 real enemy or assist the party enough so that he realizes his role is not a striker class. He had some gear but nothing too crazy either a magic pair of gloves that let him cast an extra at-will and a magic pair of boots that let him teleport 30 feet if he fell

Party is as followed. Belgoes the elf ranger, Karth the human fighter, a dwarf cleric we called tank because we didn't know his name, and me as his caster.

Session starts off like any other dialog here, go get info there, couple skill checks, a small fight (fighter and ranger kill everything before I can act, but dm is having all the enemies aimed at me *damn) then on to the mini boss.

The BBEG (next weeks boss) was a pirate who's ship was at sea, he had under his boat a kraken, 5 or 6 deck hands, and the mini-boss who was his first mate (a female pirate) but we had caught up to him before he fled the ship in the long boat.

Init rolls.... a 17 I'm near the top if the round but not first. Deckhands swam the fight, mini boss is rushing the ranger, fighter shoves a deckhand off the boat. "as soon as he hits the water, you hear him scream as the kraken eats him alive, that's the instant kill"

BBEG moves to the long boat and is about to escape/flee the map, holds his action to lower the boat though.

My turn now, I'm looking at his character, saying to myself "how do I one up this guy" I take his Gnome caster and straight charge/bull rush the BBEG keep in mind his STR was an 11. 18 to hit, just enough to push him into the water. Gm rolls his reflex save not enough to stay on.

Gm says, "since he was holding his action, as he falls he grabs the guide wires and takes you and the boat down with him." You both fall to your death as the kraken eats you alive......

In my head I'm like "hey I killed the boss, point made" but then I remember his boots. "you said I fell to my death.... I use your instant action boots to teleport back to the top of the boat." Table goes ape shit crazy as I killed the boss using nothing more than a bull rush. DM just sits there in that look of WTF and Well Played.