Simplify the following text for a Grade 16 native English-speaking person.
Original: In their first appearance in the series , the only portions of their bodies that still seemed human were their hands ; by their next appearance in The Moonbase ( 1967 ) , their bodies were entirely covered up in their metallic suits , with their hands replaced by two finger claws , but they changed back to regular five-fingered hands in The Invasion ( 1968 ) .
Simplified: In their first appearance in the series , the only portions of their bodies that still seemed human were their hands , but by their next appearance in The Moonbase ( 1967 ) , their bodies were entirely covered up in their metal suits , with their hands replaced by two finger claws , but changed back to regular five finger hands in The Invasion ( 1968 ) .