
In Halo 2, the easter egg Skulls print their names to the screen when collected, except for the Skull in the tutorial level. This is because, in the list of Skull name string IDs in the executable, the last entry (the Skull in the armory uses internal ID 14, the final of the 15 Skulls [zero-indexed] [though there's ram reserved for 16 Skull active booleans]) is unassigned, making it print a null string. Fans have called this Skull "Whuppapotamus" after a list of skull names found in mainmenu.map, though said list has a different Skull listed under the wrong name and this list wasn't localized... Upon rerelease in the Master Chief Collection, 343 Industries has dubbed the tutorial Skull "That's Just... Wrong", which comes from another Skull name list found in mainmenu.map which
was localised and has all the correct used names.... though that list has sixteen skull names (two unused, if you're following along), and "That's Just... Wrong" is the sixteenth and final entry. The fifteenth entry, the other unused name, is "Cow Bell", which i believe was the intended name for the Skull given this particular Skull's effects - sets every noise the player makes (footsteps, melees, etc) to maximum volume for the AI hearing routines, effectively making every movement a clear position telegraph for every enemy, like you're wearing a big cow bell or something......
The only issue with this is that, in Halo 3, there is indeed a Cowbell skull, which is almost identical in function to Halo 2's Sputnik skull. It's the only renamed skull in the series, and the rename has carried forward to all future Halo games. I figure 343i chose the alternate name for the unnamed Halo 2 skull to ppossibly avoid confusion (though if it were up to me i'd rename all the "official" Cowbell Skulls back to Sputnik, and have the unnamed Skull be Cow Bell).
On the subject of Halo 3 Skulls, there are two of them in the story that unlock the same easter egg & achievement - one in the first level, Sierra 117, and another in Cortana. They both are treated as the Blind skull. Some mild digging into Halo 3's main menu files reveals that the one in S117 was actually intended to have the Assassins effect from Halo 2, but i guess they didn't have enough time to implement it. Eggs such as skulls have historically been some of the last things added to Halo in the bungie days, with the Halo 2 batch not being present in any form as late as five months before release!
And to cap it all off, there's even an early version of the Skull list leftover in the Halo 2, listing only
7 with descriptions: Assassins, Juggernaut, Nosferatu, Say What?, Hudless, Disembodied Soul, and Makeover. Assassins made it unchanged into the final list, Juggernaut became Thunderstorm, Nosferatu became Black Eye, Say What? became I Would Have Been Your Daddy, Hudless became Blind, Disembodied Soul became Acrophobia(?) and Makeover survived a little longer as That's Just... Wrong before ultimately getting cut.
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