Here’s the original topic being referenced.
On the official VEX IQ legal parts list, these 2 can be found:
The one you are looking for seems to be the 4-hole variant (left one in the picture), but it doesn’t seem to be sold on the VEX website.
However, I recognize this part from the Z-360 Disk Launcher Hexbug-VEX kit. These are available to purchase all over the internet and are generally a great source of unique competition-legal parts, especially if you need a small amount of parts without that scary VEX shipping fee.