An armed conflict that supposedly took place during a night in the year 43W. Despite no proof of its existence having survived to the present day, it is a popular incident retold and recounted many times by historians and at campfires. Commonly regarded as one of the most embarrassing military failures of the age of machines.
The bunker complex of Jezioro, named after a nearby lake, had always been a fiercely contested area. Even today, as large clans have long lost interest in it due to being seen as not worth the constant struggle for it, it is considered an advantageous territory, highly attractive to teams.
At around Midsummer in the year of 43 Northern Winters, two particular clans had set their sights on it. The Eternal League had been chased out of their previous territory by a stronger clan, and marched eastward in search of a new headquarters. Coming from a southern direction, a different clan, VortexWalker's, had just been founded. It was hailing from the Festungsfront Oder area and on the lookout for their first base of operations.
Both forces had sent out scouts, which spotted each other while exploring the Jezioro bunker complex. The first severe misunderstanding of the action happened there - the scouts of the Eternal League interpreted the sightings as a clan residing in the area, while VortexWalker's scouts had seen a plane in the sky, mistaken it for three distinct free ones, and advised against attacking the complex just yet - at least until the planes would have moved on to a different territory.
The Eternal League's officers agreed that just marching to the complex from two sides and flushing out the occupying clan should be possible without any hassle or risk. It was decided that the attack should happen during the next night, so the darkness would conceal their forces.
As such, the clan's forces split up into two halves and got into position in a safe distance outside the bunker complex, about six kilometers apart. The units waited until the night, and finally started the attack.
Meanwhile, VortexWalker's forces had set up a camp a good 3 kilometers to the south and decided to put up a dummy plane - essentially a large kite that they were flying around the surrounding area in hopes of scaring the real planes away if they spotted it.
As the attack on the complex began, the Eternal League first sent out their planes to deliver an initial strike and locate the main force of the presumed enemy clan. Both of them flew over the area and reported "moving objects" on the ground, near the southern edge of the complex. While one of the planes did another flyover to deliver a strafing, the other spotted an unidentified object in the sky further to the south and veered off to investigate.
At the same time, the tanks started moving in on the area where the planes had reported their sighting of enemy ground forces. The night was a very cloudy, dark one and none of the clan's force were equipped with night vision devices, which made them rely mostly on the planes' directions. The other difficulty was that the two marching units were out of radio range of each other, which, once again, made them dependent on the planes whenever they would fly close enough to get into radio range of one of the units.
One of the units reached the suspected enemy location faster than the other, but could not observe anything similar to the planes. There were no "moving objects" anywhere, only a lake, which they could see pretty clearly from their elevated position on a hill. The unit came to a halt near the shore and deliberated for a short while, and then decided to look elsewhere for the supposed enemy clan. They started moving northward to circle the lake.
Unfortunately for them, it was about then when the other unit arrived at the scene as well. Unlike the first unit, they were travelling on even ground and did not spot the lake at all. They did however spot "moving objects", reported via radio that they had encountered the enemy, and opened fire.
The first unit, having heard the announcement and being shot at suddenly, suspected this enemy on the other side of the lake, where the incoming fire was originating. They also reported enemy contact, and quickly got into defensive positions, returning the fire.
The second unit noticed the "enemy" tanks retreating and tried to pursue, but their side of the lake had much steeper embankment than the other side - several tanks rushed ahead, simply fell into the water, and couldn't get back out. Interpreting this as a trap set up by the "enemy clan", they hastily stopped their advance and kept firing blindly into the night instead, where they were still getting attacked from. They also called in their planes for air support. The one plane that had circled above in a fruitless attempt to make out who was the enemy and who the ally, was relieved to have this conundrum solved and went to attack the first unit.
In the meantime, the second plane, which had found that the strange object in the sky had disappeared, returned. It hadn't witnessed any of the radio communication since it had gone investigating, but now it was presented with the sight of a plane firing at its clanmates. Mistaking that plane for the enemy, thinking it was the unidentified object it had seen previously, it immediately moved in and shot it down.
It went on to support its allies, but being able to listen to both sides of the radio communication, and seeing it all play out from above, finally realized that the two friendly units were firing at each other instead of any enemy. It quickly flew by both units and told them to stop attacking each other, which, after lots of confusion and questioning the plane's information, eventually happened.
The shooting ceased, and the few survivors started to realize what a clusterfuck they had just caused.
Self-inflicted defeat and disbandment of the Eternal League
2 fighter planes
Immediately following the "battle", a small scouting force of VortexWalker's Clan arrived at the scene of the events. They had been alarmed by the sounds and sight of cannonfire and explosions in the distance. The scouts were able to simply chase off the remaining, confused and frightened vehicles that had survived the confrontation.
The main force arrived soon after and occupied the bunker complex without opposition. The clan held it for a reported 12 weeks before it was fractured through a series of unfortunate events that was started by a dissent about the color of the clan's insignia, and resulted in a hostage situation that got the leaders killed.
As for the Eternal League, it had become too weak to sustain itself after the heavy losses, and also had become the laughing stock of the surrounding clans. It was disbanded shortly after the incident.
If nothing else, this combat action achieved the creation of a very popular and - to most modern machines - hilarious tale.