Kastalia

The Goddess of Lakes and Rivers. Also the goddess of Staff Thwapping, as illustrated here:

               ___
         ,.   /__ \[
         ||] |(@@)|| <--- Kastalia
         || \| \/ ||
         ||  '--|--'
         ||  |/\|\|
         ||     |
         ||    / \
 *thwap* ||   |   |
       __(}   |   |
,->  _/  \_  _|   |_
|
'--- mortal