For the comic book, see The Curse of Evil Tim.
The Curse of Evil Tim is a scam that Ed came up with in "It Came From Outer Ed." The scam is based on the comic book itself. Unlike most scams, this one was not intended to generate money or enhance the Eds' image; rather, it was simply intended to summon Evil Tim (for unknown reasons).
Most of the scam was adapted from a ritual described inside the comic book. As such, it had many steps. The first step was to paint Qs all around a plot of land (in this case, the construction site) and then gather rocks. Once the rocks were gathered, they were to be placed on the Qs. The second step was to find someone to wear odd face paint and wear a pentagram over his bare chest, a part which Eddy was forced to play. With this done, a cement mixer had to be painted like an Aztec temple, and then the shirtless man had to find some rotten spaghetti noodles. Once this was done, all that was needed was for someone to wear an astronaut helmet and a parka and for that someone to hand the oddly-painted person a plate of pancakes. Edd acted as the astronaut in this scenario.
As soon as the pancakes were handed over, however, Ed revealed the last part of his plan as he grabbed Mr. Yum Yum away from Jimmy and ran back to the construction site. The kids gave chase, only to turn back when Ed "killed" Mr. Yum Yum, treating him as a sacrifice. No profit was garnered, so in one way it can be presumed that Ed's scam was a failure. However, a minute after the kids left, a bunch of crows flocked to the site of the scam, possibly heralding the arrival of Evil Tim and suggesting that Ed's scam was a success.