A butterfly effect is the phenomeon that a small change in initial conditions that leads to a significantly different result than if the initial conditions haven’t been changed. Have you personally witnessed such phenomeon?
Example: Your pet seeks attention and you decided to spend a few seconds to pet your pet before leaving for work/a party/shopping for grocerries/etc. You drive to an intersection and the light turns red just a few seconds before you arrive, the car ahead of you passed the intersection sucessfully. When you eventually arrive at the next intersection, you find the car ahead of you was hit on the side by another car from the intersecting road. The driver in the car ahead of you was instantly killed.
You’ve just been saved by your pet.
I’m delivering papers, wee hours in the morning, middle of winter. Just had a storm recently, so roads were rather icy. Go to cross the street when my dog starts acting all weird, won’t let me cross. Just as I’m getting frustrated, suddenly a pickup truck comes barreling around the corner. Driver immediately loses control on the ice, truck goes into a sideways slide at a pretty high speed.
That truck missed me by maybe a foot at most.
Your dog is a time traveller!