(Session Report) The Summon Story

Copied from my old G+ post on the Lamentations page.

BACKGROUND:
-This was my first time running anything old-school, so I decided to run my favorite OSR system, Lamentations.
-My players were mainly used to 5e but wanted to see what the OSR is all about. They're masochists and rolled stats in order and rolled spells randomly.
-The Magic User rolls randomly for spells and gets Summon.
-Players read the 15 or so pages of rules for Summon and unanimously agree it's a Good Idea and should be cast first thing every fight.
IT BEGINS:
-First fight: MU casts Summon. Brings forth a 2 HD fungus with no special powers or properties. Fungus is Extremely Vexed and MU must choose another PC to be sacrificed to its Supreme Vexation. After heated debate under timed pressure, they choose the other magic user, who blinks out of existence to what was surely an eternity in the Plane of Mycelial Torment.
-Player rolls up his second character, and gets crazy power stats.
-Party affirms that casting Summon is still a Good Idea.
ROUND 2
-During the second session, party decides to ambush a fairly scary weapons shipment (the soldiers outnumbered them about 2 to 1 and had firearms as well as a wagon-mounted gatling gun).
-The PCs get a pretty slick ambush setup going with caltrops, triggered rockslide, and some impressive uses of lard. Everything short of bees (note to self, increase availability of bees).
-Fight starts, MU casts Summon. Brings forth a much more impressive 4 HD air creature with Humming Genitals that has 240 move speed and is immune to normal damage.
-Loses the fight to control it by a large margin. Air creature is now hostile and causes everyone within 100 ft (everyone in the encounter) to randomly switch bodies.
-I go into DM emergency mode and decide that there were 14 soldiers in the caravan, which means the total amount of bodies in the encounter are 20, so that I can quickly make a d20 chart with everyone on it so they can roll to see where they end up.
-PC Fighter ends up in PC Specialist's body. PC Specialist, MU, and Cleric all end up in random soldier's bodies. One PC's henchman and the enemy MU switch bodies. Another PC's henchman ends up as the gatling gun operator. Soldiers fill all remaining bodies.
-Complete chaos ensues.
-The air creature is attacking the PCs bodies that are filled with confused, panicking soldiers.
-All the soldiers' bodies are crammed into one wagon. PC MU in soldier's body immediately casts Summon again, bringing forth a Kelp creature who he manages to control. It appears inside the wagon, suffocating everyone in kelp. Everyone inside the wagon tries to escape, and they emerge in a disgusting kelpy pile.
-Meanwhile, the enemy MU in henchman's body casts... you guessed it... Summon. For 10 hit dice. I'm cackling maniacally. Rolls... turns out it's a balloon... with no appendages or powers... (maniacal laughter dies out). At least the enemy MU has control of it.
-PC Fighter-in-Specialist body sneak attacks enemy MU, killing him instantly.
-BALLOON IS ROGUE, repeat, BALLOON IS ROGUE.
-Balloon decides to go after its natural prey: air. It charges the air creature and the world's dumbest Kaiju battle ensues, with the Balloon winning handily and stuffing the humming-genitalia'd air creature into itself, before turning back to the main battle.
-The kelpy pile of people has performed mitosis and created two distinct masses: the PCs in soldiers' bodies and Kelpo on one side, and an enemy soldier firing line on the other.
-Kelpo charges the firing line but takes many musket shots, and finally goes down to bayonets after killing 2 soldiers. RIP Kelpo, you will be remembered in song.
-The Cleric in soldier's body has spent his time climbing up to the gatling gun, and he and the henchman in soldier's body finally figure out how to use the damn thing. They proceed to mow down the rest of the firing line due to insane rolls.
-Balloon reaches them. It rears up in the noonday sun, glorious and terrible, and defeated humming can be heard from within. It body slams the Cleric in soldier's body, taking him to exactly 0 hp.
-Henchman in soldier's body, screaming bloody vengeance, gatlings the Balloon as the rest of the PCs hack at it with machetes.
-The air creature, sensing its time is now, emerges forth through the many holes as the Balloon sags, deflated, into the dusty annals of forgotten history.
-PCs realize they cannot even inflict damage on this thing, and that the Balloon was the only thing keeping them from its humming wrath.
-PCs run about screaming and attempt many hijinks, until the MU and a henchman find a rune covered power suit in the other wagon and try to activate it by guessing words. After shocking themselves and setting themselves on fire, they activate the suit's janitorial mode and vacuum the air thing up, where it remained, humming feebly, until its summon duration expired.
-Combat ends. Time to do a saving throw to see who gets to return to their original bodies. The MU succeeds and goes into his original body. The Cleric fails, and stays in a body that had far higher physical stats than his original one (he originally had 5 CON). The Fighter fails, and stays in the Specialist's body. The Specialist succeeds and also goes into her body, creating this awkward two-souls-one-body scenario. Two of the henchmen (who were orcs) fail and stay in their new human bodies, and now face some very difficult cultural identity issues. One henchman succeeds but goes into his dead body (the one that was hijacked by the enemy MU) and dies instantly.
-PCs weigh the pros and cons and declare that Summon remains to be a Good Idea, and should be cast first thing every fight.

TAKEAWAYS: After a discussion with the players, we came to these nuggets of wisdom.
1. Cast Summon. Do it. Do ittttttttt.
2. Need a way to ensure more appendages/powers (without creating so many that the creature is unworkable). Only one creature in this entire story had an appendage and none had powers.
3. OPTIONAL Find a way to entice players to cast it more. See takeaway #1. Maybe less overtly lethal but more creatively interesting consequences for failing to control the creature.