This sounds like Acetaldehyde. It may be caused by infection (worst case), or by not enough starting oxygen for yeast, underpitching, bad yeast condition, wrong temperature of fermentation, oxygenation too late in the process, and some other reasons.
Luckily, given time yeast should be able to process it into ethanol. So if this is not an infection, just rouse your yeast back into suspension, and give it few extra weeks. If it's infection, it's lost already so why not? And for most of other reasons, it'll help.
Oh, and be really, really sure that you stay safe when tasting etc. If it's not fully fermented, it's easy to introduce infections, so tasting might be risky thing to do.
For the sake of completeness, I feel like I should mention higher alcohols. Large amounts of simple sugars might be the cause, and honey is simple sugars in most part. Also, too high temperature can be the reason. But this would happen in all carboys, wouldn't it? It should, if it's the same recipe or even batch, and they are all fermented in one room. So I don't think it's a cause here, given the OP's description. But smell fits this case, too.