Returning 1 'Morphtronic' monster from your hand to the Deck is not a cost.
"Morphtronic Accelerator" targets 1 card on the field.
When the 'Morphtronic' monster is returned from your hand to the Deck, the Deck is shuffled before the targeted card is destroyed and before you draw 1 card.
Destroying the target and drawing 1 card are considered to happen at the same time.
If you do not have any cards remaining in your Deck, you cannot activate "Morphtronic Accelerator".
If you cannot destroy the targeted card, you must still return 1 'Morphtronic' card from your hand to the Deck, but you do not draw 1 card.
If you do not have a 'Morphtronic' monster in your hand when "Morphtronic Accelerator" resolves, the effect of "Morphtronic Accelerator" disappears.