I'm researching Greek Lore and this statue keeps popping up as a reference but I can't find anything more about it. Is it still around? Was it destroyed? It's annoying how it's on a good chunk of Ares related things but there's no other info that follows it. I can't even find pictures. Anyone know about this thing?
Strictly speaking not Ares, but Enyalios. The two were originally separate, then for centuries Enyalios was treated as an epithet for Ares, then they were thought of as separate again.
We have only one isolated snippet attesting the statue. Pausanias 3.15.7, writing in the 2nd century CE:
Near is a temple of Hipposthenes, who won so many victories in wrestling. They worship Hipposthenes in accordance with an oracle, paying him honours as to Poseidon. Opposite this temple is an old image [agalma: the word actually means 'statue'] of Enyalius in fetters [pedas, literally just 'foot-bindings']. The idea the Lacedaemonians express by this image is the same as the Athenians express by their Wingless Victory; the former think that Enyalius will never run away from them, being bound in the fetters, while the Athenians think that Victory, having no wings, will always remain where she is.
'Old' might mean genuinely Archaic-era, or it might just mean 'two or three hundred years old'. We're looking at a time many centuries after Sparta's military forces mattered, anyway. Hellenistic- and Roman-era Sparta traded on propaganda about its past: most of its modern reputation was invented in that period.
This is the only primary source on this statue, so nothing further is known. There are certainly no authentic images. By Pausanias' time Enyalios should really be treated as a separate divinity, though it's always possible he was identified with Ares at the time it was made: we can't know that either.
Only a vanishingly small proportion of statues have survived from antiquity to the present, so it's not at all surprising that it didn't survive or get mentioned in any other source. Pausanias is our most detailed source on minor ancient statuary.
The question of when the idea became popular in modern reception is one I can't answer, I'm afraid.
For reference, Pausanias describes the shrine of the wrestler Hipposthenes as being east of Sparta's racecourse, near a sanctuary of Athena Axiopoinos ('Athena the goddess of tit-for-tat').