Name a Special Ability

Kinda depends on the genre. With modrn weapons there is the corner shot that might applicable, heavier weapons and you have a guided shot. With a bow, it'd be a high arc or lofted. Handheld weapons might be a spear or polearm, but lance might be even better. You could use ricochet to imply bouncing off a surface to hit bhind. High tech, I'd maybe go with a coalescing shot, implyng a diffuse energy that comes together at a further point. Could also toy around with aiming or sniper with the idea that the unit behind is partially exposed. Tunneling is another way. Magic brings in more with things like a targetted teleport, psychic assault, or such.

Spell or Lance? Pierce. But that is really only if you intend on hitting both units.

I think spell pierce is pretty common in games with magic resistance. And obviously the whole idea of a lance is to reach out and pierce the opponents armor. Bonus points if you can stick more than one guy on a single lance? :)

Also many games where arrows, projectiles, and other attacks have a chance to pierce their targets hitting the ones behind them.

If you are more about going around the guy in front, then that is a bit harder.

An aircraft might penetrate some airspace, going around defenses en route to the target.

A spell could teleport to the rear target.

A projectile could arch over the front line.

A lance... would pierce, not go around(unless you throw it?). Now the knight, riding a horse carrying the lance, would flank the front line to hit the weak rear.

Lob? The first thing I thought of was throwing a grenade, stone or other projectile over an obstacle

I was thinking more towards a unit ability versus a general ability. I like Kroz's suggestion for "reach" for a general ability.

How about "Curve"? It applies to physical weapons and projected spells.

If you are talking about lances and spears, how about

"Reach"

Salvo, Bombadment, Volley, Barrage, Enfilade, Hail...

Archer? Targeted? Precise Shot? Precision?