I think he means, do you have other locusted dummy units acting as collision missiles in your map? Do you already have something set up for this kind of thing? Coding the projectile could be kind of fun, might be good practice. I would see two ways to code the movement of the projectile:
A parabola that's been parametrized into x(t), and y(t), and z(t) functions, and you can fit "t" into whatever time interval to make it go faster or slower.
Use basic kinematic equations from physics with some fixed acceleration, speed, and projection and facing angles, checking for terrain height and unit flying heights.
The colliding with units could be done in the way Vexorian has it set up in his XE system, an enumeration over an area about twice as large as you want to detect units so that fewer gaps in the area occur at each enumeration.