I had fun drawing this.
Then, before posting, I thought Aw come on. I bet both the name and the gag have been used a zillion times. You've committed cryptomnesia!
Then I ran both through Google.
One match for "Ganderdalf" as a throwaway joke on some message board. No matches for "wand kicks like a mule". In the Googleverse, wands seem to "kick ass," often near other things that "kick like a mule."
I think I'm safe.
Wait- have I seen those trees before??