|“||Yin-Yarn used the power of the Metamato to transform into a mighty robot tank!”|
|— Mega Yin-Yarn's Cast Description • Kirby's Epic Yarn|
Mega Yin-Yarn is the transformed version of Yin-Yarn in Kirby's Epic Yarn. After Yin-Yarn's defeat, his knitting needles come to life and use the Magic Yarn that he had previously dropped to create this tank-like monstrosity. Kirby fights him in Tankbot form thanks to a metamortex dropped by Meta Knight.
Mega Yin-Yarn looks like a more menacing version of Yin-Yarn with an even more evil look on his face. He retains his hat, holds his two enlarged knitting needles in long lengths of red thread that act as his arms, and has two spiked wheels for feet. His moustache is slightly more jagged-looking and his body is spherical in shape.
Mega Yin-Yarn's main attack is continuously firing missiles from his mouth. He can raise himself up on his bladed wheels and shoot missiles in all directions when close to defeat, and will swat the Tankbot with one of his knitting needles if Kirby gets too close at the start of the fight. Kirby can shoot down Mega Yin-Yarn's missiles and shoot Mega Yin-Yarn's wheels to put him off balance to temporarily stop his missile barrage, but enough missiles from the Tankbot to the villain after he stands up on his needles will knock him down.
After several hits from the Tankbot, the evil sorcerer breaks up into many pieces of thread and his signature button, finally vanquished for good. His destruction causes his knitting needles to drop down in the process and they soon flee.
If Kirby gets too close to Mega Yin-Yarn while he's spinning around, his spiked wheels will hurt the pink hero.
- Mega Yin-Yarn's description in Patch Plaza states that he, Yin-Yarn, used the Metamato's power to transform into Mega Yin-Yarn. This is incorrect, however, because he clearly uses the Magic Yarn to accomplish this feat.
- There is also some ambiguity as to who revived Yin-Yarn into this form. Mega Yin-Yarn's description in the patch plaza would suggest that Yin-Yarn revived himself into that form, but both the actual cutscene and the playing guide (which notes that "Yin-Yarn may be finished, but his wicked knitting needles aren't!") suggest that this transformation was actually performed by his knitting needles, the latter even implying that Yin-Yarn himself might not have been conscious during the battle. It is therefore possible that Yin-Yarn was dead and/or simply being controlled by his knitting needles.
- Mega Yin-Yarn's battle theme is an extremely sped-up version of Yin-Yarn's theme.