Monster Eggs is a concept used within the Japanese dub that was never mentioned in the English dub.
When fossilized, Time Shifters become a monster egg, which can be easily sent through the timeline to a specific point in time to aid Flint and his friends. Turning a Shifter into a Monster egg also protects them from being transformed into their Bad Transformation. However, a Shifter already in this state cannot be transformed into a Monster Egg.
In the English dub, they were just said to become a fossil and were never addressed as "Monster Egg".
Monster eggs were introduced as a concept in the Bros. comics, in the Bom Bom comics they do not exist. This makes Wolfen the only named Shifter without a Monster Egg outside of The Land of Dread Time Shifters. Originally they appeared as a egg with mysterious natures and the name of the Time shifter was written on the egg. In the anime, they were given unique designs based on the Shifter's appearance.
List of Eggs
|Time Shifters||Lovelove | Jitterbug | Eldora | Talen | Mosbee | Cocoron | Bubblegum | Lynx | Artie | Batterball | Ammon | Elfin | The Cardians | Monarisu | Wing | Moah | Elekin | Muscles | Unita | Raldo | Leafy | Monk | Nightcap | Musey | Change | Bugsy | Dipper | Knuckle | Doron | Shadow | Orbit | Dorimon | Wolfen | HaniWani | Hanasaka | Funga | Hyururu | Ekoeko | Nioja | Deathdas | Nascal | Gera|
|Locations||The Land of Time | The Land of Dread|
|Keepers||Old Timer | Dark Lord|
|Forms||Monster Eggs | Bad Transformation | Super Transformation|