|Artwork by Capcom
The Yoku Block (a name mainly used by fans; their official name is Appearing Block) is a recurring gimmick in the classic Mega Man series, making its debut in the original Mega Man, and appearing in nearly every classic Mega Man platform game since (with notable exceptions including Mega Man 8, Mega Man IV, Mega Man V, Rockman & Forte: Mirai Kara no Chousensha, and Mega Man 3 for DOS), and even some later series with the Mega Man title, such as Mega Man X and Mega Man ZX. It is a block that appears and disappears in a pattern.
Being one of the series' most notorious gimmicks, Yoku Blocks were made available as early as the original Make a Good Mega Man Level, where they appear in the entries Sunset Siege, Wily Combo, Hard to See Land, and Thunderclyffe Plant, as well as the Wily stage Flashback Database. Yoku Man also uses the gimmick in some of his attacks, and in Make a Good Mega Man Level Remastered, the gimmick appears in a brand new room in The Quickening if the Skip Teleporter is taken.
Yoku Blocks return in Make a Good Mega Man Level 2, where they appear in 12 entries, as well as the Wily stages Classic Castle and Reality Core, the Tier X levels Deep Thoughts and Hardcore Parkour, the Pit of Pits mini-stages "Discount Yoku Man", "Feelings", "Labyrinthe Throwback", and "Mega Man a - Area 2", and in Null and Void. The contest also introduced Yoku Spikes, which appear in Snow Man, Quirky Unconsistent Incomprehensible Nonsensical Track, and Classic Castle.
By contrast, Make a Good Mega Man Level: Episode Zero saw more restrained use of Yoku Blocks, with the gimmick only appearing in Temporal Pillar, Construction of Constructions, and Entrance to Tier X. Yoku Spikes, meanwhile, make two appearances in both Entrance to Tier X and Ice Breaker.
Yoku Blocks appear and disappear in a set pattern, meant to work alongside other Yoku Blocks to create either a linear path or a group of blocks that must be jumped on in a specific order to get from point A to point B. Yoku Block patterns will often try to throw Mega Man off by placing a Yoku Block in a location that Mega Man must jump to from a Yoku Block that is just about to disappear, or right above Mega Man so that he must jump straight upwards to avoid being dropped off the block he's currently standing on.
Yoku Spikes function the same as normal Yoku Blocks, except they kill Mega Man upon contact.
Yoku Block designs
Yoku Blocks take on various appearances throughout the series, ranging from blocks from existing Mega Man games to all-new blocks. The functionality doesn't change between these blocks; just the sprite.