Meaning of the word "dod" in "Mr. Icky"

Hello. This is not a literary comment but a language inquiry (I did read the forum rules, it seemed ok to post this here...)

The word "dod" appears several times in this play, and I can´t for the life of me figure out what it means.

First passage (obviously a word-play): "Mr. Icky ... is pottering and doddering among the pots and dods."
Second passage: "There is no sound except an occasional cackle or hiss from the dods as they quarrel among themselves."
Third passage: "Several more of Mr. Icky's children ... trip over the pots and dods."
Fourth passage: "He [Mr. Icky] finds a Bible lying in one of the dods and opening it at random begins to read."
Fifth and last passage (where Mr. Icky talks about not finding a suitable passage in the Bible for his teaching purposes because its being damp): "There was water in the dod. It won't work."

What's this thing which quarrels, can be tread upon and has water inside? Or is it just a nonce-word?

Thank you very much in advance!

First of all, I personally think that this play is very.... meaningless.
Anyway, back on topic.

First passage (obviously a word-play): "Mr. Icky ... is pottering and doddering among the pots and dods."
Obviously, it's something that can be placed on the floor with pots.

Second passage: "There is no sound except an occasional cackle or hiss from the dods as they quarrel among themselves."
This can be read figuratively. This "object" or "thing" can be personified to fit this description.

Third passage: "Several more of Mr. Icky's children ... trip over the pots and dods."
It's obviously small enough to be tripped over.

Fourth passage: "He [Mr. Icky] finds a Bible lying in one of the dods and opening it at random begins to read."
It can contain something, a bible, in this case.

Fifth and last passage (where Mr. Icky talks about not finding a suitable passage in the Bible for his teaching purposes because its being damp): "There was water in the dod. It won't work."
It can contain water and it is obviously not alive.

Conclusion:
A "dod" is a cauldron with something inside them. In this case, some have water boiling inside, one has a bible, and others are just empty.

For those with stubborn imaginations: It could be a chicken or a cat. :D