From the animated TV show Grim & Evil (08/01/2003). This Nazi-helmeted trio-turned-quartet appeared in the "Battle of the Bands" episode of this almost-watchable cartoon. As a trio, PF play generic hard-rock riffage, occasionally pausing so the lead singer/guitarist can whisper "Purple Filth."
Then they meet the Grim Reaper, who grabs the leader's pink, heart-shaped guitar and rips some Malmsteen-y licks that loose demons from hell and burn down the neighborhood. Later in the episode, we see the now four-member PF on stage at the battle of the bands. They're kicking out the jams in a vaguely Motorheadish (with less interesting vocals) way.
Then Billy (remember Billy? It's a show about Billy) and his dad, painted like a cross between KISS and Braveheart, crash the stage. Billy ends up winning the whole schmiel by arm-farting "The Farmer in the Dell." And thus, another lame battle of the bands episode comes to a close.