Weird looking Celeriac

[MelanieSW]

Amongst my bed of strapping healthy looking celeriacs, I have this weird reddish and stunted looking thing.
I don't think it's contamination as I've used mainly my own home-made compost plus a few handful of commercial compost. And none of the other plants is affected.
Does anybody have any idea what the problem could be?

[Thelma Sanders]

I'd dig it up, my bet is on something eating the roots, so the plant can't absorb nutrients.

[Nicos]

Very strange.
I've had a look around to see if there is a red leaved/stemmed variety which might have accidentally got into your seed packet, but can't find one. (There IS a red celery however)

Might be worth cutting off the old leaves...the new ones coming through look healthy ( or are they stunted?)? And see what happens?

[MelanieSW]

I finally dug it up today out of curiosity - and it looked perfectly normal. No damage to roots, and a small but round celeriac bulb.
Now I kind of regret it - this might have turned into a new variety...