Unfortunately, the duck is the lizard's natural enemy...

If you recall, about a week ago, Arthur came across what he believed to be a duck egg (Coral cache). Immediately, some sort of primal, "motherly instinct" (evidently only found in male ducks) kicked in, and Arthur felt obligated to care for the abandoned egg. On Sunday, we discovered the appalling truth (Coral cache).

I mention this only because I find uncontrollable joy in watching the subtle changes in Arthur's face, panel by panel, as he comes to the horrendous realization that ducks are born as hideous green lizard-like monstrosities. That has to be a difficult fact to come to terms with.