Ambush.
The word is raid or ambush.
air raid
Ambush.
stab
to break down the courage of completely, as by sudden danger or trouble; dishearten thoroughly; daunt: The surprise attack dismayed the enemy.
The word "raid" can function as both a noun and a verb. As a noun, it refers to a sudden attack or invasion, while as a verb, it means to conduct a surprise attack or invasion on a place or group.
Mercurial means quick and changeable in temperament.
Surprise Try using a Thesaurus for more words that mean surprise.
alarm
jog is quick where did you get this question from.
speedy, quick
Shock. It comes from the surprise attack on the town by the Germans in WW1. A Scarborough Shock is to be struck without warning. Not in common use.