Little kid facing monstrous mice is sending a message (7)
I believe the answer is:
totemic
'sending a message' is the definition.
(totemic can mean symbolic or with special meaning)
'little kid facing monstrous mice' is the wordplay.
'little kid' becomes 'tot' (I've seen this in another clue).
'facing' is a charade indicator (letters next to each other).
'monstrous' indicates an anagram.
'mice' is an anagram of 'emic'.
'tot'+'emic'='TOTEMIC'
'is' is the link.
(Other definitions for totemic that I've seen before include "(Of an object) having spiritual significance" , "Relating to an important symbol" , "Like something significant" , "Having significance as an emblem" , "like a sign" .)