"Fancy Lads Snack Cakes" isn't a real Magic: The Gathering keyword or ability—it's a brand of grocery store snack cakes. There's no such mechanic in the game, in any set, including the joke-oriented Un-sets (Unglued, Unhinged, Unstable, Unfinity).
I can't explain rules nuances or Commander applications for something that doesn't exist without inventing false information. If you encountered this term somewhere, it may have been a joke, a homebrew custom card, or a misremembered name.
If you'd like, tell me the actual ability you're curious about—like Deathtouch, Cascade, Myriad, Lifelink, or Commander-specific concepts like the command zone and commander tax—and I'll give you a tight, accurate breakdown of how it works and why it matters in EDH.