It looks just like a regular berry pie, with a golden brown crust and filling inside, but is actually a very powerful explosive that detonates when dropped or thrown. It will also explode in a few hours if eaten, killing whoever is unlucky enough to eat it.
Role in episode
"Dying for Pie"
It is Employee Brotherhood Day at the Krusty Krab, so Squidward buys a pie from a group of pirates for SpongeBob. However, the pirates inform him that they are actually bombs rather than pie. Squidward is left disappointed, saying that he was planning on buying one for someone. Wanting a quick buck, the pirates lied by telling him that they are not actually bombs, enticing him to buy one.
Once SpongeBob eats the pie, Squidward then realizes that it is actually a bomb and decides to make SpongeBob's last few hours of his life meaningful as can be as a result.
However, it is revealed that SpongeBob did not eat the pie and it was in his pocket the whole time for him and Squidward to share. Unfortunately, he trips and the pie lands on Squidward's face, causing it to blow up in a nuclear-like explosion, destroying Bikini Bottom in the process.
Role in video games
Exploding pies can be used as a weapon to knock the player's opponents off track.
Plankton's Robotic Revenge
There is a Gizmo (gun-type weapon) called the Exploding Pie Launcher that launches exploding pies as projectiles.
Despite the destructive power of the pie, it is apparently only lethal when eaten, as Squidward, Mr. Krabs, and SpongeBob are barely fazed when it blows up near them.