Mania uncontrolled, student becomes beast (6)
I believe the answer is:
animal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">beast</span>' is the definition.<br/ ><span class="explanation-format__explanation">(a beast is an animal)</span><br/ ><br/ >'<span class="explanation-format__original">mania uncontrolled student</span>' is the wordplay.<br/ >'<span class="explanation-format__original">uncontrolled</span>' is an anagram indicator.<br/ >'<span class="explanation-format__original">student</span>' becomes '<span class="explanation-format__intermediate">l</span>' <span class="explanation-format__explanation">(as in L-plates for learner drivers)</span>.<br/ >'<span class="explanation-format__original">mania</span>' is an anagram of '<span class="explanation-format__intermediate">anima</span>'.<br/ >'<span class="explanation-format__intermediate">anima</span>'+'<span class="explanation-format__intermediate">l</span>'='<span class="explanation-format__answer">ANIMAL</span>'<br/ ><br/ >'<span class="explanation-format__original">becomes</span>' acts as a link.<br/ ></span>
(Other definitions for animal that I've seen before include "Organism having life" , "Brutal, sensual" , "Uncivilised person" , "One sharing our kingdom" , "Circus performer, maybe" .)