Skelesaurus

The monster effect "①: While this card is on the field or in the GY, it is treated as a Normal Monster" is an effect that is not classified as an Ignition Effect, Trigger Effect, Quick Effect, or Continuous Effect.

The text "(2): You can Normal Summon this card while it is treated as a Normal Monster to have it become an Effect Monster with this effect" is not treated as a monster effect.

When you Normal Summon a Gemini monster that is treated as a Normal Monster and is face-up in Defense Position, it remains in face-up Defense Position.

The monster effect "● This card's Type and Attribute become Dinosaur/EARTH" is a Continuous Effect.

The monster effect "● When this card destroys an opponent's monster by battle and sends it to the GY: You can Special Summon that monster to your field in Defense Position. The monster Special Summoned by this effect becomes Zombie-Type" is a Trigger Effect that can be activated optionally. (It does not target. It is an effect that activates at the end of the Damage Step when "Natural Bone Saurus" itself destroys a monster by battle and sends it to the GY.)

If "Natural Bone Saurus" battles a monster with the same ATK and both are destroyed, you cannot activate the monster effect "Special Summon that monster to your field in Defense Position."