Appearance:

The enderman in Minecraft Dungeons looks mostly the same as in the base game, with the only difference being its eyes. The eyes have glowing white pupils instead of purple, and its eyes are also brighter than its base game counterpart.

Behavior:

Endermen teleport away after taking damage, and can damage heroes heavily. They also can hide within teleportation and not appear right away. They cannot teleport inside walls. An Enderman attacks only if attacked first, if the hero comes too close, or if the hero looks directly at it for too long. A defeated enderman does not drop its body. Instead, it raises its arms and opens its mouth to scream its death sound as it fades away.

More Info: https://minecraft.fandom.com/wiki/Minecraft_Dungeons:Enderman