An answer like this is
a) not a yes or no, and thus usually not allowed in such dilemmas. That’s also why “I just tap it lightly on the head” is not a real answer. There is no valid “outside the box” answer for dilemmas. Your valid answer seems to be “no”, since you would not kill that animal, the rest of your answer is just … unimportant to the question asked.
b) disregarding that you’re going to jail for murder and aggravated robbery. You have just taken your own life (to jail)
The cuteness of the creature being a factor is something I absolutely understand. Although I’m entirely in love with arthropods and reptiles and all those creepy crawlers, I would still feel worse about the bunny.
It’s an instinctual thing, as mammals we’re genetically programmed to love baby mammals and protect them. We usually empathize more with them and some of us even tremble with good feelings when watching or touching them. It is inherently rewarding to pet them and to show them kindness. So it’s no wonder we can easily crush something like a roach or a fish. It’s harder with chicks and even harder with rats or baby kangaroos since they check more and more of the boxes activating that instinct.
Instincts just that though, we are completely able to ignore it, desensitize or rationalize. Luckily we’re (mostly) ruled by our minds and not our instincts.