Just something that seemed like a cool idea that wouldn't go out of my head. Say a simulation had two species of algae; one is something like A. minimalis, the other one is a 'building block'. This means it produces vast amounts of poison and shell to make it hard to feed off. When a bot ties to it, it starts producing vast amounts of slime as well, to stop any future ties. The two would use an I/O channel or some other method of communication to differentiate from each other.
The challenge is to create a bot that, without trying to feed off the building blocks, uses them to create a nest or defensive structure. For example, you could place them in a circle around a fixed point to creature a fortress, with other bots inside the fort harvesting the normal algae and other bots pushing on the opposing structures to try destroy them. To make it interesting, ties cannot be used to share resources or information (strictly physical bond), no viruses, .sexrepro or venom is allowed (eg. no messing with the algae), and no poison or shell (this forces you to use the algae as protection). Summary: F3 plus physical ties.
