[nonsapreiche]

not to mention the cell that is a chicken egg

[samatman]

It is the yolk of an egg which is the single cell / ovum in birds.

And yes, if there's a larger cell than an ostrich yolk I'm not aware what it is.

[sedatk]

Biologically, an eggshell isn't a cell wall.

[stjohnswarts]

ostrich egg?

[randoglando]

Ostrich yolk technically