"So Guppy, Daddy needs to have a talk with you."
"Well, I want you to know that when Mommy comes to pick you up from Michael's house, you need to go with her. You don't make Mommy wait for you, you don't whine about not wanting to leave, you don't make Mommy chase you around the house. It makes it difficult for Mommy and late for her to pick up your brother."
"No buts. You're a guest there, and it makes it very awkward for Mommy. You have to listen to Mommy, it's important."
"But Daddy, why did the caterpillar die?"
"We're not talking about caterpillars right now, honey. Did you understand what Daddy just said about listening to Mommy?
"What do caterpillars eat?"
"And if you make Mommy so very angry
"Oh. Okay, Daddy."
Let's see if it this sticks for the next 24 hours. Before she finds the next caterpillar.
(P.S. Check out this neat site, Farecast. Thanks to them I waited it out and got better rates, and my husband has been saved from being tied to the stake and given a royal lashing. Now he only owes me $12.)