Often, when a character has a new body they will flex their hand to test its response. Also applies after regrowing an arm. Examples: Bleach- Ulquiorra regrows arm- arm check. Dragonball Z- Cell gets a new form- arm check. Mummy- Imhotep reattaches severed arm- arm check.
Hello, Unknown Troper. You'll need to get known to lend a hand here.