One thing about the original problem. Anything with inductance; coils, motor, electro-magnets etc, can cause high voltage spikes when turned off. If your motor drivers are of a switched type, they may be the cause.
Second, the probes usually have setting slike 1x, 10x, x100 with 10X is the most common. The X is actually a divider, ie a 10x probe divides the signal by ten, and if you set the scope input to X10 it will multiply the result by ten to get the right reading. When working with inductors, coils, set the probe to 10x or better 100x until you have seen what the signal looks like. That will give some protection to your scope from high peaks.
PS You can see an inductor and causing an inertia for elecricity. Trough ann inductor, Current is "hard to start, hard to stop", has inertia. A traditional car ignition coil is simply a magnetic coil that you run current through. When you cut the current, it has "nowhere to go" but converts into a high voltage spike. In cars, this converts 12V to short ignition spike of several thousand volts.