Nearest enemy unit?

Ok I'm making a skill called chain hex, basically its like chain lightning but it hexes all the units it hits, what I need to know though is if theres a way to make it affect the nearest enemy unit, I also don't want it to target the same unit twice so I was wondering if polymorphed units are the same as hexed units. Any help would be appreciated, thanks in advance!

Polymorphed units, have the poly buff on them. Hexed units, have hex buffs on them, so no they arn't the same.

um, i'm tired so there might be a better way, but

set distancevar = X
set closestunitvar = no unit
pick all units in range X of unit Y
-- if distance between picked unit and unit Y <= distancevar
-- -- set distance var = distance between picked unit and unit Y
-- -- set closestunitvar = picked unit
-- endif
endloop

Assuming chain lightning targets the closest unit (which I believe it does), can't you just use a chain lightning with zero damage, and then trigger: If unit is hit by chain lightning, cast hex on that unit?

@PCPharaoh
yeah, but unless chain lightning creates a buff on the units it hits for a second, this idea will fail.

So use triggers to add a useless buff on the unit, and then use hex on them.

but that only gives u the first unit. How are u going to third unit or even fourth.