An egg slicer can duo also as a mushroom and strawberry slicer.

But there is one "however".  The mushrooms must be absolutely fresh and firm.  If they are the least bit  soft it won't work as well.  So if you have fresh, firm mushrooms simply set them in the cradle of the slicer making sure the cap is towards the hinged end.

Give it a little pressure...

and you have slices.

It's pretty cool.  The other thing it slices beautifully is whole strawberries.  I don't have one on hand to show you but I'm sure you can figure it out.  It really is a time saver.