What is big and grey and has 16 wheels?
An elephant on roller skates.

What is big and grey and has 2 trunks?
An elephant going on holiday.

What is big and grey and hides in the wardrobe?
An elephant that owes money.
What else?
An elephant afraid of the thunder.

What is big and grey and lives in a Scottish lake?
Nessie the Elephant.

What is big and grey and makes a horrible noise?
An elephant playing the bagpipes.

What is big and grey and needs no ironing?
A drip-dry elephant.

What is big and grey and plays squash?
An elephant in a cupboard.

What is big and grey and protects you from the rain?
An umbrellaphant.

What is big and grey and red all over?
An elephant with nappy rash.
What else?
A sunburnt elephant.
What else?
An elephant embarrassed by all these elephant jokes.

What is big and grey and sings jazz?
Ellaphants Gerald.