Electric current by definition is the flow of electrons. That is what electricity is. Electricity — like water flowing through a pipe — can be stopped by preventing its flow.
The flow of electrons can be stopped by doing what is termed “breaking the circuit”. That means by terminating the wire or conductor material so that the electricity cannot move along that path.
The sparks you see in the cases of static electricity and lightening result from their circuits having been opened — broken and therefore terminated.
In these two cases the voltage (pressure) was great enough to make the current jump the gap. In the first case, the gap may be between your finger and another person; in the second case, the gap is between a cloud mass and the earth.