If somebody asks you to do something, and you think this is too ridiculous or simply impossible to do, you can give one of the following answers. They all mean more or less “No way!” or “Forget it”.

Ja, da-ag!

(yes, goodbye)

Dacht ‘t niet!

(didn’t think so)

Vergeet ‘t maar!

(just forget it)

Geen denken aan.

(won’t even think about it)

Ik pieker d’r niet over.

(won’t even consider it)

Kom nou!
(Come on)

Ben je helemaal belatafeld?

(are you crazy?)

What does belatafeld mean?

tafel = table

la = drawer

be-la-tafel-d =>  to be table-drawered ? ??

Well. It actually doesn’t mean that.
It is only a way of saying…that you must be out of your mind