Solarmite

Solarmite was an explosive substance. The modified CCPC, Pain-Maker, was modified with solarmite so that when he was fired upon by K9 Mark 2, he would take K9 with him. However, K9 refused to fire, and escaped before Pain-Maker self-destructed. K9 would later reveal that while solarmite would damage him, the only explosive force capable of destroying him was his own self-destruct function. (K9TV: Robot Gladiators)