Mobs are in-game entities with AI, that aren't players but can interact with players.
There are currently 54 mobs in Mine-craft.io.
Like Minecraft, there are 3 types of mobs: Hostile, Neutral, and Passive.
Hostile Mobs will attack players that are not spawn-protected when in range, and players can avoid being attacked by 1) Killing it 2) Running away 3) drinking an invisibility potion 4) using /fly, /god, or /vanish, (only available for Youtubers and staff members), 5) teleporting away or leaving the world . All boss mobs are hostile.
Neutral Mobs will attack players only if the player deals damage or interacts with them in a certain way.
Passive Mobs will not attack the player under any circumstance.