Hurl Boulder based spell

I am using a spell based on hurl boulder, except it just deals an initial damage of 355. I wanted to make a buff that appeared on the targeted unit as soon as it is targeted. The spell has a chance for the target to evade the projectile, so I wanted a buff that warns the owner of the targeted unit. In this case I wanted to use the exclamation mark from the campaign and have it appear above the unit, with the appropriate buff icon on the actual unit. So far I have been unable to do this because the Hurl Boulder buff relys on the spell lasting for some time once it has hit.

Base the spell off something like Cluster Rockets (AoE). When spell effect starts, pick all units in AoE and create exclamation mark above them... then when spell effect ends remove it or after some time.

That would work, accept I need this to be a single unit target spell like Hurl Boulder.

maybe something like dummy unit with attack ancient protectors had before patches (can be avoided) and When unit is attacked add exclamation mark...

you can't make hurl boulder/storm bolt and stuff with chance to hit :S

Best way imo is to trigger everything, base your spell off something that adds a buff, make it add the buff you want. When u detect casting w/ triggers, create an evadable projectile with triggers or like jacek suggested with the dummy unit attack.

If you want to copy dota spells the best way to do it is to look at dota's war3map.j. Chances are you can even find an old version with this done in GUI.

Uhm, i found a nice idea for you. You can base your ability on Panda's spell which slows and make you miss (don't remember the name xD). Set its area of effect to 90 (or similar), then turn off the "follow target" field (it has a similar name. Now, when your unit casts the spell, you have to show the special effect on the target and then remove it if, after some time (let's say 5 seconds) the target has not the buff. I think that it should work...

I'm not home to try this out but this should be the gist of it.

He wants the buff on the unit right when the projectile is launched.

That would also work, but you must make your own buff system first.

There is no "add buff" trigger in the editor, there is only remove buff.

Thats what I said, you need to make your own buff system to do that, so my way is the best.