"Limits" around units.

[Razthemapper]

I want to make an "Dissapear" ability that teleports the caster randomly around the target (around another unit). Is there any way to set "limits" around the unit?
Ex: Hero A casts "Dissapear" on Unit A , Hero A blinks somewhere around Unit A , within some limits that are a kind of circle around Unit A , it's somehow like blink , but the caster does not select the location , it selects a unit, i don't think i explained it very well , tell me if you want me to reexplain , I know how to teleport units but I don't know how to set "limits"
Also , the caster can not get teleported outside the limits!

 

[AceHart]

Unit - Move instantly, with "point with polar offset".

Unit - Move instantly (Casting unit) to Position of (Target unit of ability being cast) offset by (random between 200 and 500) towards (random between 0 and 360)


The "between 200 and 500" is the distance from the targeted unit.

 

[Razthemapper]

Thanks a lot , I really needed that help! My ninja hero is almost done! Thanks again!