It happened on my July vacations at my grandparents' farm. It seemed just like another common day, but we were about to find out it wasn't. We "kids" went for  an erosion that there is near the house.
We slid there and ran and walked through a stream and threw some kind of purple clay and water at each other. After we get annoyed of playing there we went to the river so we could perform some somersaults and swim in there.
We went through the forest and we started hearing some noises which remembered us of a horror movie, so we started running just to make fun. We were pretending that the guys from the movies were chasing us. So we got to the river, had some fun and wrestled in the mud. But we soon saw something movin in the water and we got out of it. We looked at that place and saw this huge snake, it was a anaconda (not from those unreal shown on the movies, it was definitely smaller).
We ran and ran until we get in a place in which we could be safe. We stopped there and rested a little. Then we heard a weird meow (not those ones we hear coming out of a cat's mouth, it was chesty). So we assumed it was a jaguar and started running since we couldn't do anything to protect ourselves. We  climbed trees and waited up there until my grandma shouted it was Dinner Time.
We ran there and we told my grandparents and they said it was very dangerous to stay there without an adult, a knife and a gun. But thanks God it was the last day of our vacation and then we had to go to the city again, other way we couldn't have any more fun and adventure. Anyway it was the greatest vacation ever and I was glad to take part in this experience.

Post Scriptum: these facts didn't happen at the same day, only put them all together to make it more interesting and some of them might not be true at all.