(This one I an alternative ending to the story of marble stuck on the toilet trying her best to poop, but nothing comes out.)

Maud came back home with a special potion for marble, she entered the bathroom with marble on the toilet
Maud: I got this potion that should help you, marble
Marble immediately grabs the potion and drinks all the liquid the bottle had and gave the empty bottle to Maud. Marble then was preparing to poop again, while Maud let her poop in peace.

After a short while marble's belly was growling violently, she has a lot of hope for the potion to work and hope that she can finally leave the toilet. She begins to push really hard, as hard as possible, as hard as her body allows her. She keeps pushing, and pushing, and pushing, and pushing and suddenly, she hears and feels a loud splash in toilet water, and it splashes her butt a little. She looked inside and there was a giant log of poop. Marble started to smile, but more growls erupt in her belly causing her to focus on pushing again. Much more poop are squeezing out of her butt and marble was pushing much harder and the poop was then getting more wet and squishy. She looked inside and there was much more poop inside the bowl, she got worried that the toilet would get clogged, so she closed her butthole preventing more poop from coming out, and grabbed the flush rope and pulled it, flushing the toilet under her. She was holding the poop real hard and the water drops hitting her butt, didn't stop her. Thankfully, the toilet didn't got clogged so she opened her butthole again letting more poop out.

50 minutes passed, and she's still on the toilet pooping for real, she flushed another time, and let more poop out of her butt, but a minute later, her butt drops no more poop, she was scared by that, and tried to push more and more but nothing comes out. Marble then realized that she can't poop now, because she's now done pooping. On that though, she got finally happy and leaned her back and head against the wall and she could finally get reliefed.
After a minute of happiness, she flushed the toilet once again and she started to slowly get up from the toilet, she stumbled on the floor a little, and walked away from the toilet.
Suddenly a small fart startled her a little bit but anyway, she got really happy that there were no more belly growls and that she can finally leave the bathroom. She almost left the bathroom, because she forgot to while her wet and dirty butt, she did that right now, washed her hooves and finally marble left the bathroom with a cute smile on her adorable face.