An 200+ mm abomination that combines design elements from various large-caliber rockets:
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Caliber from S-24/25 unguided rockets (which are 240 mm in diameter), but not specifically warhead (explained below).
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Purpose from 122 mm S-13 - destroying reinforced aircraft shelters/pillboxes
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And speed from AGR-14 ZAP - it was intended to reach Mach 3 after launch, although for slightly different purpose I want to suggest here.
Alternatively you can look into MGM-166 LOSAT, but with warhead, but it was not aerial,
It is a really large guided rocket, propelled to high speeds by its solid rocket motor, but range-limited (probably to 6 km only). Because of its size it is limited to 2 per rail (unless it is something like outer rails on Compass, than it either 1 or none at all).
This weapon is intended to disable bunkers and similar structures with only a few hits (better than anything that isn't Auger or nuke). To properly work against them it also has to accelerate for a few moments, which makes its minimal range rather large, at 2-2.5 km, depends how fast its shooter was flying. It does have explosives in its warhead, but in smaller quantity than its size might suggest.
It can and will absolutely murder any ground vehicle as well of course, but due to limited maneuverability and small launch window it will struggle to hit moving targets smaller than a ship.
Speed is also limiting its guidance choice, it is a command (well, inertial/GPS with datalink updates, think how ALND works), which could also lead to misses if target disappears from datalink (e.g. you plane/helicopter was the only spotter and got shot down).
Because it is a rocket, it can be locked by IR SAM (but they might struggle to reach it in time), and does not make evasive maneuvers, which, combined with reduced salvo size compared to Lynchpins make it vulnerable to SPAAGs and CIWS.