Editing Mega Baby Bowser

Big Baby Bowser debuts in ''[[Super Mario World 2: Yoshi's Island]]'' as the true final boss in said game and its [[Yoshi's Island: Super Mario Advance 3|Game Boy Advance version]]. He is fought after defeating Baby Bowser right before Kamek casts a spell on him. The final battle takes place on the remains of the room; at the beginning, Big Baby Bowser sends debris down to destroy part of the ground. During this phase, Big Baby Bowser attacks by breathing fireballs at Yoshi, advancing from the background. If Big Baby Bowser gets too close to the castle, the ground will be destroyed, instantly defeating Yoshi. The player must grab the [[Giant Egg]]s that [[Item Balloon|Baron von Zeppelin]]s carry onto the stage and throw them into the background at Big Baby Bowser to knock him back. After three hits, Big Baby Bowser again sends debris down to destroy part of the ground. After enough hits, he simply charges forward, and after seven hits, he is defeated, returned to his normal size, and knocked out; it is possible to land this last hit even if his charge destroys the ground Yoshi is standing on, resulting in a slightly different final cutscene. Afterward, Kamek reappears and vows revenge before flying off with Baby Bowser. Yoshi then sprints up to the [[Stork]] and [[Baby Luigi]], freeing them both and allowing the Stork to deliver the babies to their parents.

Mega Baby Bowser is the true final boss in ''[[Yoshi's Woolly World]]'' and ''[[Poochy & Yoshi's Woolly World]]'', battled in {{id|King Bowser's Castle|YWW}} following the Baby Bowser battle. He again sounds like Bowser Jr. After Baby Bowser is defeated, Kamek uses the [[Wonder Wool]] to create large eight magenta versions, in order to transform Baby Bowser into Mega Baby Bowser. The size increase is so drastic that Mega Baby Bowser pops the roof off of the tower in the castle containing his room, knocking Yoshi and Kamek away. This cutscene incidentally also removes Yoshi's supply of [[yarn ball]]s. Yoshi lands on the tower's edges and engages Mega Baby Bowser. This is an invisible checkpoint in King Bowser's Castle; dying during this battle restarts at the cutscene where the tower's roof pops off. Note that many [[Power Badge (Yoshi's Woolly World)|Power Badge]]s have no effect during this battle.

This battle occurs on a circular tower, with three large [[cannon bobbin]]s placed equidistant from each other. The parapets of the tower mean the arena has uneven but consistent terrain. On the side opposite of each cannon bobbin there is a darker black portion of the parapets, these will be relevant later. Mega Baby Bowser stands inside the tower, while the eight large Wonder Wools float around his head. Mega Baby Bowser opens the battle by creating and throwing six giant [[yarn ball]]s of varying colors into the air. All of them descend onto the tower, landing at varying times and knocking away the highest blocks of the parapets. The landing points are in between the highest points of the parapets and the cannon bobbins. The yarn balls inflict damage as they fall, but after landing are normal ground. Note that this attack causes the large Wonder Wool to float off screen. Each of the yarn balls have [[bow (object)|bow]]s on them if they land face up, these can be [[swallow|eaten]] to unravel the entire yarn ball and create three [[big yarn ball]]s. This animation takes a long time given the size of the yarn balls in question. Yarn balls that are face down do not have visible or usable bows, but if Yoshi uses a [[Ground Pound]] near an upside down yarn ball while using the "Power up Ground Pound!" Power Badge, the yarn ball will flip right side up. With big yarn balls in Yoshi's possession, Yoshi can use the [[Egg Throw]] to aim into the tower, similar to throwing eggs into the background in ''Super Mario World 2: Yoshi's Island''. If he hits a large Wonder Wool, that Wonder Wool will be dispelled. In ''Poochy & Yoshi's Woolly World'', [[Poochy Pup]]s are equally useful, and the infinite supply of normal red yarn balls available while all three Poochy Pups are out of reach also work. Mega Baby Bowser ignores any and all other attacks, with projectiles bouncing off his body, but he is defeated once all eight Wonder Wool have been destroyed.

Mega Baby Bowser turns to track Yoshi, but if Yoshi is far away it takes time for him to catch up. Since the Wonder Wool floats relative to Mega Baby Bowser's head, attacking the Wonder Wool positioned behind him is fairly difficult. Mega Baby Bowser cannot turn while he uses an attack. One of Baby Bowser's attacks is to point at where Yoshi is then bring his hand down on that spot. This knocks away any of the large yarn balls he tossed in away if the attack hits them. Mega Baby Bowser can swing into thin air, to no significant change to the attack Mega Baby Bowser uses this attack twice in a row. Another attack is to prepare and launch a large stream of [[Fire Breath]], starting from either Yoshi's left or right and sweeping in the opposite direction. This can be avoided in two ways. Yoshi can jump over it, possibly with assistance from with the stacked yarn balls. Yoshi can hide below the height of the flames using the parapets. Lastly, Mega Baby Bowser can jump into the air, turning to face Yoshi no matter where Yoshi is. The landing causes several fire pillars to rise up from the tower in multiple directions. Only the last set of the pillars can hurt Yoshi, but since the pillars rise in a wave pattern in a straight line, the earlier ones show where the later ones will end up. The impact can flip over some of the yarn balls in the arena, revealing or hiding their bows in the process. If the number of yarn balls in the arena drops too low, Mega Baby Bowser will repeat the opening attack.

One way to defeat Mega Baby Bowser is to make use of the cannon bobbins. None of Mega Baby Bowser's attacks can hurt Yoshi as long as he is inside one; only the flame pillars can reach him and those cannot hurt Yoshi. If the player has the cannon bobbin fire Yoshi out, they send him to the opposite side of the tower, landing at the opposite darker black portion of the parapet. Once Yoshi shoots out, Baby Bowser will be confused and stand in place while looking for Yoshi, interrupting his attacks. This gives ample time to attack the Wonder Wool at or near Mega Baby Bowser's backside. After a while, Mega Baby Bowser will jump to face Yoshi again. Note that every time Mega Baby Bowser lands, Yoshi gets forced out of any cannon bobbin he is inside. Additionally, the cannon bobbins will fire in the opposite direction around the tower compared to where they did before the landing.

After dispelling four of the Wonder Wool, Mega Baby Bowser staggers back and his Wonder Wool float off the screen again. In [[Easy Mode|Mellow Mode]], this is the only portion of the battle where Mega Baby Bowser drops [[Heart (item)|hearts]]. He starts over, this time throwing six giant black yarn balls into the air. More yarn balls rise into the air than the ones he threw. These yarn balls are even bigger than the ones prior to this, and they destroy much of the tower's terrain. Only the three darker black sections of the parapets and the cannon bobbins remain, though the black yarn balls land in neat stacks of three. The stacks are positioned in the same six way split the earlier yarn balls had. One larger yarn lands in the center of each space, while the other two land on top. They lean on the remaining blocks and the blocks holding up the cannon bobbins. Each stack of three has one yarn ball of a non-black color land on top, which did not appear with the earlier rising yarn balls. The black yarn balls never have bows appear. To finish the battle, Yoshi has to attack the remaining four Wonder Wool, while noting that Mega Baby Bowser's hand attack now knocks away the primary ground of the battle, leaving behind [[pit]]s. It does not have this effect on the lowest and centered yarn ball of every stack, which makes for additional safe space that is uncomfortably close to the pits. There is also no space to crouch under the fire breath attack, requiring that Yoshi quickly unravel a colored yarn ball or have Baby Bowser knock part of a stack away to create room should that be the player's decision on how to dodge. When the yarn balls on the tower run low, Mega Baby Bowser can again replenish them, this time throwing both black and non-black ones while summoning more.

In the [[Boss Tent]], Baby Bowser's Boss Challenge also includes Mega Baby Bowser, fought directly after normal Baby Bowser. There is no checkpoint in this version; dying while fighting Mega Baby Bowser means starting from Baby Bowser again. While the cutscene of the transformation is skipped, Yoshi's yarn balls are still lost in the transition. Mega Baby Bowser's speed increase while fighting him in the Boss Tent makes him substantially more difficult to fight. It is harder to run away from his attacks and access the Wonder Wool close to his back. Also, the rate Yoshi can unravel one of the yarn balls in the battle remains constant despite the increased attack speed from Mega Baby Bowser, leaving Yoshi very vulnerable while obtaining big yarn balls. Instead of the ending cutscene playing out, Yoshi's position is reset using a fade to black for the victory dance.

Mega Baby Bowser returns in ''[[Yoshi's Crafted World]]'', where he is fought after defeating the [[The Great King Bowser|robot that was created]] for Baby Bowser through his wish before Kamek uses the [[Sundream Stone]]'s Power. This time, Mega Baby Bowser wears a crown hiding the Sundream Stone and has a slot machine-esque armor which appears to show how much health he has. After being defeated, Mega Baby Bowser shrinks back down to normal Baby Bowser.

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|JpnC=<ref>''[[Super Mario-kun]]'' [[Super Mario-kun Volume 15|volume 15]], page 57</ref>