Six-footer I see in prank (5)
I believe the answer is:
antic
'prank' is the definition.
(I know that prank can be written as antic)
'six-footer i see' is the wordplay.
'six footer' becomes 'ant' (an ant has six feet).
'see' becomes 'C' (the word for the letter, according to Chambers).
'ant'+'i'+'c'='ANTIC'
'in' acts as a link.
(Other definitions for antic that I've seen before include "Playful or mischievous act" , "Caper, trick" , "Ludicrous act done for fun" , "Prank" , "Frolic" .)