Fallout Shelter creatures

Overview
Among the many incidents that can happen to any vault, creature attacks will be among the most common, and can take the forms of both random and instigated attacks.

Creatures that will attack a vault
At the moment, only standard deathclaws will directly attack a vault. They will be an uncommon sight at first, randomly appearing whenever a radio station is active, or whenever a vault door is opened. However, once a vault gains 60+ vault dwellers, or 35+ vault dwellers on Hardcore, they will become much more common, and will begin to phase out raider attacks.

Instigated creature attacks
While rushing any room, and then failing said rush, there will be a large chance that either radroaches, or mole rats will attack that room, before spreading to other rooms if not contained in time. Both mole rats and radroaches will multiply if there are no targets in the room, or if no vault dwellers are sent to enter the room within a short period after they spawn. Mole rats' and radroaches' strength depends on the level of the room in which they spawn, and should they be allowed to multiply, they will eventually spread to each room of a vault, and kill everyone within it.

Creature encounters while exploring
Creatures of all sorts can be encountered whenever a vault dweller is sent out to explore the wastes. Should the vault dwellers manage to kill these creatures, they will earn XP. Should a dweller be too weak to kill certain creatures, they will escape, should they manage to survive the encounter, and will gain ten percent of the original XP.

Mammals
Mole rat

Creature encounters while exploring:

Reptiles
Deathclaw

Creature encounters while exploring:

Arthropods
Radroach

Creature encounters while exploring: