The code would read like this:
"If enemy is overlapping jumper, then enemy jumps."
Just make a sprite called jumper and put them on your map. If you want to make the jumping feel random or spontaneous as a dodge, you can put chance based jumpers.
"if random(0, 100) is greater than 50 and enemy is overlapping jumper, then enemy jumps" will only make half of the enemies that collide with the jumper jump.