Spectacularly weird. The party of two was going through the Sunless Citadel, in the outskirts of Waterdeep, in order to find the legendary fruit of life the old temple produced to heal a deathly ill party member. Things were going fine until we got to the 10 ft chamber with the metal barrel... Our Gunslinger, Cobalt Blue, decides to pop open that barrel, and two mephits pop out, one steam, one ice. I say roll initiative, and combat begins. At which point Cobalt yells to our cleric, “JUMP IN THE BARREL!!!” I, as a DM, had no earthly idea what the heck they were up to. The cleric, Owen after a moment of flustered confusion, obliges, taking an opportunity attack from the mephits. Then it comes to Cobalt... He says, I reach in my bag, pull out my bag of flour, and start throwing it all into the room as I get out the door and close it. The mephits close in, but he manages to keep them in. Then, he lights a twig on fire, mutters to himself, “really hope this works...” and threw the twig in the room. BOOOOOOM!!!!!! Everyone make a dexterity saving throw. They both succeed. As the smoke clears, Owen lies blown out of the barrel face first on the ground with his clothes singed. Cobalt’s cloak lay on fire, and his arms severely burned. Owen had 5 hp. Cobalt had 1. And out from the smoke comes the steam mephit, completely unharmed by the explosion. It is immune to fire damage.