Something in the River

Hallowe'en, thirty years ago.
We had spent the day ghost hunting (as usual) around the woods of Kinloss. It was a Sunday. This I remember because the usual trick or treating ritual was done on the Friday, so as not to offend those with Christian principles on the Sunday.
I remember the sun over the tops of the trees to the north of Burnside, that late October light, all serious and mysterious and full with the thoughts of those deep, cold nights to come. I remember the light on the grass, all pale and drawn, and as the afternoon progressed to nightfall, the sun became full and reddened. Leaves on the ground that crackled underfoot, the colour of long nights and dark mornings.
I was halfway down the path to Burnside from the woods. My two friends were still up near the woods themselves. I'm not sure what they were doing, but as it got nearer to evening, the woods began to adopt an unsettling aura, and so I had begun to retreat to the safety of Burnside where I lived. Then my friends were running, and in that moment of pure terror, a kind of euphoria; I knew I had to run too, even though I didn;t know (yet) what they -and I- were running from.
Back at Burnside, one of my friends said that he had seen 'something in the river'. He never described it fully,  (because he was making it up obviously). I wasn't there, and never saw that there was nothing in the river, so I have spent the last three decades wondering what might have been glimpsed in shallow river  north of Burnside.