The day after a massive missile attack on Ukraine on December 16 which resulted in almost 80% of missiles shot down, the russians remembered they still had unused P-800 "Oniks" supersonic anti-ship cruise missiles from the "Bastion" coastal defense system.
According to the Operational Command "South", early morning on December 17, russian forces in the temporarily occupied Crimean Peninsula fired off two Oniks missiles aimed at the Odesa region. Both were successfully intercepted by Ukrainian air defense.
Presumably, this way russians were trying to "finish off" some facilities of Ukrainian critical infrastructure but failed to do so.
Over the past three months, it is only the second attack. And there is a notable episode during one of the last attacks with the use of Oniks missiles. In late August, shortly after the launch one of the missiles fell down and exploded in Crimea due to malfunction. The only time they used Oniks since then was a single strike on the Mykolaiv region in October.
During these months of pause, there was another related story: russia was reportedly asking India for these missiles. The data published later on by Ukrainian General Staff stated russia had spent quite many Oniks, along with other types of their cruise and ballistic missiles. As of November 18, russian forces had spent 123 Oniks out of 470, or roughly 25% of the total.
The new attack on December 17 proved russians were still willing to diminish their stocks, however, Ukrainian air defense on its part has adapted and learned how to counter these supersonic missiles.