UPDATE 14/10/20: Pokémon Go developer Niantic has provided Eurogamer with a statement on this week's addition of 12km eggs, and specifically their introduction so soon after the recent removal of the lockdown half hatch bonus. I also asked Niantic if it had any plans to offer more detailed information on the likelihood of hatching certain creatures from eggs - a key fan concern.
"We had planned the introduction of 12km eggs for some time - they are a permanent addition to the game, so players can take their time collecting and hatching them," a Niantic spokesperson told me. "We want to continue to encourage players to exercise safely wherever possible. We're also actively listening to feedback regarding the egg hatching experience, and we'll share more on this front when we're ready."
ORIGINAL STORY 13/10/20: Pokémon Go has added a new type of egg that requires you to walk up to 12km to hatch.
Dubbed "Strange Eggs", they contain Dark and Poison-type creatures including several new species not available anywhere else, as well as the highly-sought after Deino - the focus of August's egg event controversy.
The addition - only the second time Pokémon Go has added a new distance class of egg to the game since its launch - comes just a couple of weeks after developer Niantic rolled back a couple of key lockdown bonuses, including a half hatch distance modifier for eggs.
A current week-long event to celebrate the permanent addition of Strange Eggs currently offers a more generous quarter hatch distance modifier - though this will disappear in seven days' time.
Currently, Strange Eggs are the only way to obtain new arrivals to the game such as Pawniard, Vullaby and Sandile, each of which also have multiple evolutions to obtain.
But top fan reddit Silph Road has determined the Strange Egg pool to also contain largely-unwanted species such as Absol and Trubbish, which could also pop out of the egg after 12km.
Strange Eggs are obtained when fighting Team Rocket Leaders, the mini-bosses you must fight six Team Rocket grunts first in order to track down. You will also need an egg slot spare to receive a Strange Egg, which complicates things. Ensuring you have a spare egg slot requires you clear one first, and then keep it clear, which can be difficult when interacting on a PokéStop to fight Rocket characters.
Ahead of last night's Strange Egg announcement, Niantic had suggested its tired selection of Pokémon available in eggs would be reshuffled. Currently, fan research suggests this did not happen, and only 12km eggs were introduced.
Eggs - and more specifically, their incubators - are one of Pokémon Go's key methods of monetisation. The fact their various pools of contents and chances of hatching rarer creatures consistently remain opaque has attracted a good deal of criticism - including here on Eurogamer - particularly after the chances of hatching rarer creatures are observed to have been quietly changed behind the scenes.
We've contacted Niantic for more information on Strange Eggs, and their long-term usage in the game.