Night attacks.

[PMBardunias]

Philopoemen is famous for a night attack on Nabis of Sparta's camp with what is often considered the first dedicated spec ops force.

14. Understanding that in consequence of this disaster his enemies despised him, thinking that he had altogether given up activity on the sea, and that they were insolently besieging Gythium, he promptly sailed against them when they did not expect it and were careless because of their victory. He landed his soldiers by night and led them to the attack, set fire to the enemy's tents, burned down his camp, and slew many of his men.

https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Plutarch/Lives/Philopoemen*.html

I wrote an article for Ancient Warfare Magazine on this that I could share if you contact me.

[Erpingham]

what is often considered the first dedicated spec ops force.

I'm sure Gideon did it earlier.  Another example of a successful night attack to add to the list.

[PMBardunias]

what is often considered the first dedicated spec ops force.

I'm sure Gideon did it earlier.  Another example of a successful night attack to add to the list.

It is not the night attack that made it special, it is the Spec Ops unit.  The normal practice was if you needed something done commando style (ok, not THAT commando style, they were all wearing skirts) then you sent off some sly hill people like Agrianes or Cretan mercs.  Philopemen seems to have trained up a local Achaean unit specially in the style of hit and run fighting he learned in Crete.

[Erpingham]

It is not the night attack that made it special, it is the Spec Ops unit. 

I think Gideon still got there first.  A specially selected team, specially equipped with musical instruments and hidden torches intended to surprise and defeat the enemy through panic rather than brute force. Was that not special ops?