My story takes place in dense woodland on highly uneven terrain in a temperate climate on Earth as we know it (e.g. central Europe), except a certain sort of magic is in operation.
In this woodland, there are a few very small objects which magically cause life around them to evolve extremely rapidly within a short radius, 1-5 metres. The mutation rate is higher than normal and there is no intelligence guiding this process, although I am happy to play god and guide the process a bit for the sake of interesting results.
I am imagining this would kill complex life forms since the mutation rate would be too high to allow seeds, fetuses etc develop normally. The main effect is on unicellular organisms which can sustain having large numbers of cells mutate themselves to death, the survivors will simply take their space in a short time.
This effect has been in place for a few decades, and as a result, there are these small pockets of life in the woods which are dominated by highly evolved and highly over-specialized unicellular life forms.
For example, if a fungus is growing on a rotting log, this fungus will be better than any other fungus on Earth at making use of rotting logs. However, after the log has rotted completely away, the fungus might perish since it has over-specialised.
The weather is relatively stable. Annual frosts, a few hot weeks, nothing extreme by our standards. Let's say that significant changes in the life forms takes a couple of years or more, so some (but not all) mutations will survive the cycle of the seasons.
Wind, rain, and the passage of animals will disrupt the edges of these pocket ecosystems, so these modified life forms will spread somewhat.
What absurdly over-specialised features might we observe after a few decades, and how might they interact with each other and the surrounding normal ecosystem?