Prankster's projectile (3)
I believe the answer is:
pea
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prankster's projectile</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pea that I've seen before include "Leguminous seed" , "Cause of a princess's insomnia?" , "It grows in a pod" , "It grows in 23 Down" , "Legume" .)