One song about two topics, with a bonus and also related topic (feel free to use it folks)

Odd Projectiles

The Martian invaders are coming
Those enemys so arch.
There's only one thing to stop them
They're allergic to starch

Projectile potatoes
Launched from an orbiting gun
the one thing better than SDI,
Steve Bennett Number one

For our problem he's the fixer
In a rocket powered mixer
The number one elixer
And this just ain't no trick sir

In Canada they have the chicken cannon
For testing airframes and birds
We'll combine it with the potato gun
For the latest word

The latest word in fast food
Well make the fastest food around
For we deliver every day
At half the speed of sound

We promise your delivery
No sir we aren't shivery
Gizzard neck and livery
20 milliseconds or its free