Mothers's idioms

[Devil's tear]

Hi dear teachers. I'd like to know what do these idioms mean in English?

the child from hell.
the mother of all something.
***
Thanks in advance.

[Snowcake]

child from hell:

the most unpleasant person you can ever imagine.

It's also possible to replace child by another noun.

the mother of all something:

(be) an extreme example of something.

e.g.: Eurozone breakup would trigger the mother of all financial crises.

Regards,
Snowcake

[Devil's tear]

child from hell:

the most unpleasant person you can ever imagine.

It's also possible to replace child by another noun.

the mother of all something:

(be) an extreme example of something.

e.g.: Eurozone breakup would trigger the mother of all financial crises.

Regards,
Snowcake

Thanks a bunch Snowcake. I quite understood.