"A big gray elephant"

Translation: Duży szary słoń

[Felicia279224]

wielki szary słoń?

[Jellei]

Well, normally we'd treat "wielki" as something bigger than 'big'... but here it does make sense indeed I guess. Added now.

[Simeon1969]

Would a big old grey heffalump be Duży stary/zy szary słoń? Try saying it quickly!

[Jellei]

Duży stary szary hefalump ;) Or "duży stary szary słoń" indeed.