Ants. I'd never think I'd see the day, but it happened.
Ants group A are part of a colony that mostly resides near the trees in front of most of the houses in that area. They're quite large as far as I know, as their colonies appear to cover a tunnel network of hives connected through each tree's interlocking roots. Their hives cover at least 70 meters.
Ants group B are more to the south, sticking near the channel and outwards towards the dry baked soils and the lush bushes far, far away, which probably migrated with the flying males. Ants group B could possibly just be a splinter force of foreign Ants group D that were really successful in establishing a home.
Ants group C are North East of Ants group A, and cover... Well, it's a large park, and they cleared out most of the competition. What separates the three colonies are two things : natural large bodies of still water, and flowing water, and lots of bricks.
Ants group D are various groups of garden faction ants. During the winters there are usually only around there dominant hives per garden, but every summer they spread from garden to garden, building hives beneath every tile of land and beginning the conflict anew.
Other ant groups are not too important in this account, although there is a massive group of ants west of all of the ants, but was too far away to pose any threat to the other colonies. At one point, I've witnessed 18 separate colonies in one garden - my garden.
What followed is what happened when the colonies meet.
1. Careless child drops chewy drumstick. Child disappears. Chewy drumstick rests in the sun, melting slightly and embedding in between the brickwork of the path.
2. Ants group A returning home to get out of the baking sun stumble upon the chewy drumstick. Some return home, others try to take pieces of the drumstick, only to have their jaws caught in the sticky treat, cementing them in place to die in the baking sun. Others were... Assimilated more directly into the drumstick.
3. Reinforcements arrive to try take bits of the drumstick back. Pandemonium occurs, some ants tearing loose strands off successfully, others getting stuck on other ants, more getting absorbed by the malicious sugars. The puddle increases in surface area, trapping more ants.
4. Ants from Ants group A send more ants to recover more drumstick sugars, dead ants and not so dead ants.
5. This leads to a noticeable oval of ants forming around the drumstick.
6. Water drainage scatters a group of Ants group B into the tree-where they bump into Ants group A and quickly note them to be a from a rival hive. They begin to fight.
7. Ant scouts from Ants group C cross the upper bridges (a dangerous task) to find a Jam sandwich someone had left lying around, but are instead met by the ever increasing oval of ants from B and A.
Ants group A have a colony beneath a tree which they use to hold the other end of the bridge, and emerge to fight Ants from Ants group C, believing the hive to be under danger.
8. Ants from Ants group D begin harvesting the jam sandwich, unknowingly alerting Ants from Ants group B to the location of the food, causing yet another fight. A splinter force of Ants group C takes of with a piece of sugary biscuit. Ants from Ants group B have made it to the chewy drumstick, but have little success with taking any whilst under attack by Ants group A. Meanwhile Ants group C sends even more ants over the bridge to respond to Ants group A successfully repelling them.
9. Ants group B begin sending a sizeable contingent of ants from the lower bridge (which they cover, and is slightly safer to travel on), where they fight a mix of Ants group A, C and D on a vertical face. The fallen ants begin fighting at the bottom of the steps, working their way up. Ants group A hold Ants group C off at the tree, but with overwhelming numbers Ants group C push their way to the drumstick by going through the lower steps - straight into Ants group B. Ants group D successfully secure the sandwich, but are beset by 2 more colonies of Ants group D, and they begin fighting amongst themselves.
Tl:dr, there were more ants in once place then I've ever seen in one place in my life, and they were all fighting.