Fool on the Ed is an April Fool's Day-themed episode of Ed, Edd n Eddy. It originally premiered on March 8, 1999.
The episode starts with Eddy sliding into Ed's room, where his friend is making a model. When Ed asks for the glue, Eddy goes to get it, but notices a trap. Eddy manages to firstly dismantle the trap and prank Ed, and then rig Ed's trap so that Ed is pranked again. They then head off to Edd's house, where they find him tinkering with a chemistry set. When the phone rings, Eddy does as Double D requests and goes to answer it, but senses a trap when he reads three sticky notes on the phone inviting him to pick it up. Eddy smartly pretends to pick it up and pretends to talk into it. When he insinuates that the call is for Edd, Edd is surprised and accidentally causes a chemical explosion. This isn't all for Edd, though; Eddy comes in and tells him that there's a girl on the phone for him. Edd swiftly rushes out–straight into a trap Eddy has set.
After Eddy has pranked both his friends, he marches up to them, bragging about how he is the king of pranks. He then suggests that he'll be able to prank every single kid in the cul-de-sac before sunset. His friends come with him on the expedition. The first stop is Rolf, who is busy feeding the hogs. Strange goings-on are afoot, however, as when Rolf steps into his shed for a minute, he is swiftly tossed out in a butter churn barrel. When the Eds rush over to check it out, Ed finds a card atop the barrel. On the card are written the words "Prank Master".
Eddy tries to shrug it off and goes to find his next victim. While walking down the lane, however, they run into Jonny, who is diaper-clad and hanging from a tree. The Eds laugh at this sight until Plank falls from the tree, with a familiar card tacked to his face. Ed pulls it off, and the signature from before is shown. The Eds are all fearful, but Eddy tries to disguise his fear by pointing out anyone could prank Jonny. When he looks back at the tree, however, Jonny has disappeared.
Eddy tries to get his friends to relax, but is unsuccessful since he as well is scared. The fear becomes too much for him, and he takes off running, his friends in hot pursuit. As they run, they encounter several other victims of the Prank Master, including Jimmy, Sarah, and Kevin. Trying to find a place to hide, they dive into the sandbox, only for Prank Master cards to rain down on them. Edd, terrified, notes that they're next.
When we next see the Eds, they're wearing makeshift helmets and carrying basic weapons. They're also in an outside-facing ring in order to make sure nothing and nobody can creep up on them. Soon enough, they find something suspicious: a stray jawbreaker. While Ed wants to simply eat it, Edd and Eddy demand testing. Eddy therefore nudges it twice with his hockey stick. The second nudge is harder than the first, and the sweet rolls down the sidewalk to the curb, straight into the path of Sarah and Jimmy. Jimmy picks it up, licks it, and begins to eat it. Seeing this, Eddy realizes that the jawbreaker wasn't a fake at all, and they've lost their chance at one of the sweets. When he tries to blame it on the other Eds, however, Ed points out that Eddy was the one who thought it was a trap. In response, Eddy tells them to look another way and ties Edd's hat to his underwear. In retaliation, Ed wedgies Eddy, and both Edd and Eddy join in by giving Ed a pants wedgie. The Eds are all cheered up by this bout of wedgies, but soon their attention is drawn to the laughter of another group. This group is the kids, who reveal that there never was a Prank Master and that they all faked being pranked. Eddy is sickened by this, and angrily declares that he'll get the kids back as they walk off, leaving the Eds alone.
Later that day, the kids are playing in the Cul-de-Sac. Eddy isn't preoccupied with this, however, as he and his friends have more sinister plans. They are building an El Mongo Stink Bomb from a recipe Eddy's older brother had given. Once the final ingredient is put in, they ready it for deployment. The bomb moves forward towards the exit of Eddy's garage. It seems as though things will go off without a hitch when the bomb catches on the garage door and becomes stuck. The Eds desperately try to move it out, but are unable to budge it. The bomb explodes while stuck, sending atrocious fumes across the cul-de-sac and perhaps through the whole of Peach Creek. The kids are hit horribly by the stench and rush to get inside. By far the worst hit are the Eds, however, who were right next to the bomb when it went off. Dazed by the stink, they stumble outside and collapse on Eddy's lawn, victims of their own prank.