Hurried over to find most of whale, tusked whale (7)
I believe the answer is:
narwhal
'tusked whale' is the definition.
(I've seen this before)
'hurried over to find most of whale' is the wordplay.
'hurried' becomes 'ran' (running is a kind of hurrying**).
'over' says the letters should be written in reverse.
'to find' means one lot of letters go next to another.
'most of' means to remove the last letter.
'ran' backwards is 'nar'.
'whale' with its final letter taken off is 'whal'.
'nar'+'whal'='NARWHAL'
(Other definitions for narwhal that I've seen before include "Small Arctic whale" , "Animal with large spiral tusk" , "Small tusked whale" , "Ocean mammal" , "beast" .)