Erik's Curiosa curiously makes an appearance in Beta in what appears to be a Curio. It has an Alpha symbol rather than the Beta symbol, but is found in Beta packs. This card is not an official card listed in this set, so if you pull it out of a Beta box, you've got yourself a Curio!
The company was coy in saying that the Beta set would have 402 cards compared to Alpha's 403, and it was wildly speculated that it would be removed from Beta. In a sense, it was (in the core set), but here it is in Beta packs with the Alpha symbol. The illustration seems to be a bit wider than the core Alpha set copy and there are subtle differences in the print quality as opposed to alpha, but otherwise this one can be tricky to discern from actual Alpha copies...so be careful out there!