Enderman heavy point:you become a mutant enderman. You gain 8 extra damage, 7 extra armor and 55 extra health. You also gain access to the abilities teleport, telekinesis, clone and scream.
Enderman walk point:you become an enderman. You gain 5 extra damage and 20 extra health, and gain access to the abilities teleport and scream.
Teleport:you teleport to the location your looking at.
Telekinesis:you telekinetically grab a block your looking at, when you press the key again you throw the block, with the damage depending on what block is used. For example a block of wood will do much less damage than a block of iron.
Clone:you make two illusory clones of yourself that can attack for you.
Scream:you unleash a loud distorted scream, causing nausea, weakness and slowness for 10 seconds to all nearby creatures (within 20 blocks or so).
Passives
Hydrophobia:you take damage from water
Ender eyes:anyone who looks directly at your eyes will be blinded for 5 seconds