Place to study cause of limping in fantastic beast (7)
I believe the answer is:
unicorn
'fantastic beast' is the definition.
(I know that Unicorn is a type of fantastic beast)
'place to study cause of limping' is the wordplay.
'place to study' becomes 'uni'.
'cause of limping' becomes 'corn' (corn is a lump of skin on the foot).
'uni'+'corn'='UNICORN'
'in' is the link.
(Other definitions for unicorn that I've seen before include "Mythical white horse with one horn" , "Fabulous one-horned animal" , "Singularly horny creature of fantasy" , "Team of three" , "Imaginary creature with one horn" .)