Another box & another mystery vegetable!

My fortnightly veg delivery arrived earlier in the week and I am left with another mystery vegetable! Here's a photo:
At first I thought it could be celeriac, but it doesn't really look like the photos I have found on the web - they all look more bulbous and not as smooth. Then I thought it's probably something really obvious - like a root vegetable with the top left on - what do you think?
The rest of the box contained:

• Rainbow Chard (so happy - this was yummy last time)
  
• Celery (another full bunch - I'm going to have get creative to use it all!)
  
• Carrots (also overloaded on carrots at the moment - it's OK though, I made carrot cupcakes for a bake-off at work this week which used a few)
  
• Potatoes
  
• Onions
  
• Zucchini
  
• Jap pumpkin
  
• Parsnip
  
• Capsicum

Oh, and here's a random photo I found of the hot dogs we had for dinner earlier in the week. We use Sanitarium hot dogs, mine are smothered in cheezly, wholegrain mustard, tomato sauce and soy mayonnaise - it may not be the healthiest dinner out there but it sure does taste good!