Three years ago we started cleaning mother-in-law's flowerbeds from stuff we didn't like to see there. It was pretty much so we hired a tiller and started. But we didn't know what we were dealing with. The most common plants were:
https://en.wikipedia.org/wiki/Campanula_rapunculoides
https://en.wikipedia.org/wiki/Stellaria_media
https://en.wikipedia.org/wiki/Lupinus
And all of them were quite happy for our use of a tiller. They spread! All over! And now I have been using a fork and my hands to get rid of all these terrible rootsystems. None of them are useable in the hobby. But last year I came up with a little gem! A foal! That survived the tiller!
The missus vaguely remembers it. So it probably been there for quite some time.
This year I found a horse! One of her brothers vaguely remembers it. So it's the same there.
My guess is that it is a Giant horse or a copy. I only had Airfix in the smaller scale.
The wonder is not that they are there, children play and lose stuff all the time, but that they have survived.
And here they are together with Strelets horse: