Oddest (and cold-blooded) tactics definitely bring Olga of Kiev to mind. According to the Tales of Past Years/Primary Chronicle Olga of Kiev was left the official regent of Kiev Rus when her husband was killed by Drevlians when their son was only three years old. The Drevlians wanted Olga to marry their prince. The Drevlians sent twenty of their best men to persuade her to marry and effectively give up power over Kiev Rus. She had them buried alive and then sent word to the prince she would accept his offer, but required the most distinguished Drevlians to join her on the journey so her people might accept the marriage. When the prince and his men arrived, Olga invited them to clean up in their bathhouse. Once they were inside she locked the doors and burned them alive.
Olga then invited yet more Drevlians to attend their funerals. Once she had them drunk her soldiers killed more than 5,000 of them. Olga then amassed an army and besieged their village to kill off the survivors. The Drevlians begged for mercy. Olga decided three pigeons and three sparrows from each household would be tribute enough. The Drevlians complied. Then Olga had sulfur tied to every bird and ordered them released. When the birds flew back to their nests, they set the village on fire to flush out whatever Drevlians were left. Even if parts of this story were fabricated or exaggerated later on, there still has to be some real bizarre tactics at the core of it all.