brand of biscuit
which has been in circulation
since at least the 1970s.
Consists of a layer of mallow
between two large slabs of biscuit and covered in chocolatey flavour
Highly prized for it's magical powers
as a child calmer and comfort food
Also notorious for it's sudden transformation sometime in the 80s to a smaller version of itself.
Since many of us grew up in the 80s, this change had been attributed to a simple increase in subject mouth capacity, although recent (unverified) research indicates that the biscuit did indeed shrink at some time over said decade.
If any readers are lucky enough to have an intact 70s Wagon Wheel (perhaps found in a recently-unearthed time capsule), please contact me.