Let's say your object is at x=0 and y = 300. You need it to move to y=100 and then stop. You COULD use 8-direction like so:
Object.Y > 100
(Make sure you set it as custom movement in the properties)
Or you could use bullet like so:
Object.Y <= 100
- > Set Bullet Behavior Disabled
(The reason it wants to go right is because it always "forward". lets say your object is a rocket ship facing upwards, to fix this you need to open the object editor and rotate it 90 degrees clockwise so that the direction it needs to go is facing right, then just set the angle to whatever is needed.)