This comic is based on the following short story by Kassaz:
https://www.fimfiction.net/story/526921/26/short-stories-with-pregnant-ponies/its-defective

This is the version with dialogue and without full body paint.

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“I’m certain to win that costume contest for expecting mares with this.” Twilight Sparkle spoke to nopony in particular, but to a particular dragon.

“Yeah, yeah, what are you exactly?” Spike, a baby dragon, was sleepy so late at night.

“I’m a globe!” Spike muttered. The unicorn’s legs looked wooden; her belly was painted. “My belly is an accurate world map projected onto an oblong spheroid. Everypony is sure to notice.” Spike tried to roll his eyes, but yawned instead.

Twilight walked across the room, and slid her hindlegs skillfully underneath herself to sit on a pillow at her desk for a moment. She made a note, felt a shift, and stood again after some effort.

“Oh no, I’m lopsided, and now it’s inaccurate! I have to recalculate now! Spike, get me the paint, and my abacus!”

Later, Pinkie Pie had a jail cell painted on her belly, and won.