I hate to have to link to the x-birdsite, but https://twitter.com/ToughSf/status/1769958999279927787

Rocket propellants are often fun. This one is designed to fuck things up on a magnitude that's up there with Project PLUTO, by using elemental fluorine reacting with liquid lithium _heated by cesium-137_.

For when you absolutely positively have to fuck literally everything that so much as looks at your exhaust funny.