Weeg

In Super Mario 64, if Mario approaches a Bob-omb without being seen and stands close to its spawn point, it will continue walking in a straight line without ever turning around as long as it does not encounter any obstacles or uneven ground and Mario does not move away from the spawn point. Note how it walks straight ahead in the footage despite its usual behavior being walking in circles.

If it encounters a slope while walking, it will change directions. If it happens to change directions in such a way that it looks directly at Mario, it will see him no matter how far away it is at that moment, even if it would never be able to see him from that distance under regular circumstances.

Taken together, this results in the bizarre scenario seen in the footage, where Mario is doing literally nothing while the Bob-omb first decides to walk extremely far away, suddenly "realizes" Mario was there the whole time, and attempts to pursue him only to explode before even reaching him.