You were probably fishing for something else but the sudden hit, dashing runs and drumming of his shaking head tells you you have another jack on your line. Rather than being disappointed, you should just relax and enjoy the fight. Considering spirit instead of availability, the jack crevalle would be a prime target. Jacks often travel in packs and will create havoc in a school of baitfish. That same feeding frenzy spells pure excitement for a young fisherman.
Jacks love to trap their prey any place where the prey's means of escape is restricted.
Almost any structure or edge may serve this purpose. Seawalls and the surf are excellent places to look for them. Remember, a lure cannot move too fast for a jack to catch.