The bestiary is a new addition to The Binding of Isaac: Afterbirth † that is accessible through the "Stats" menu. The Bestiary shows information and statistics on all encountered monsters and bosses except for some alternate forms of some enemies.
It shows the number of times an enemy has been encountered, how much health it has, how much damage it has done to Isaac, how many times it's been killed, and how many times it has killed Isaac.
The order of the monsters starts with Rebirth enemies, then Afterbirth enemies, then Afterbirth+ enemies.
Encountering a boss while fighting Delirium does not count towards the bestiary.
Seeded and challenge runs will affect bestiary entries, including whether an enemy has been found at least once or not, meaning that regardless of whether achievements are disabled or not, bestiary entries will still be updated.
This also means that enemies spawned using the developer console will be counted as well.
While fighting Hush, the Blue Boil will count as an encounter but the Blue Gaper will not. A Blue Gaper must be found on its own to be marked as an encounter.
Pages
These are the monsters on each of the bestiary's pages
(Click on the images to open the corresponding monster page. [WORK IN PROGRESS])
Sin collector - Collect every entry in the Bestiary (bugged v190 - Mobs that don't exist in the bestiary are being counted. This allows Sin Collector to be unlocked without a complete bestiary).
Trivia
Cross Stoneys are not featured in the Bestiary because they only appear in the Aprils Fool challenge and were added as a joke by _Killburn revealed in a tweet made on April Fools Day.
Bugs
Bug!
The Bestiary is bugged with bosses that have multiple parts (such as Larry Jr., Pin, The Hollow, and so forth).
For Pin, The Frail, and Scolex, each body part counts as an encounter and a kill.
For Larry Jr. and The Hollow, only their heads count as a kill but each part counts as an encounter.
Bug!
The Binding of Isaac: Rebirth
