When Hidden Blade targets an opponent's unit (Mindsplitter), and the opponent responds with Flight or Fight to move that unit out, does Hidden Blade fizzle completely or does its controller still draw 2 cards?

Ruling: When Hidden Blade's target becomes illegal (moved out by Flight or Fight), the spell resolves but does nothing. The controller does not draw 2 cards because there is no legal target to determine "its controller" from.

Sequence:

• Hidden Blade is cast targeting Mindsplitter
• Flight or Fight is played in response and resolves, moving Mindsplitter out
• Hidden Blade resolves with an illegal target
• The damage/kill effect doesn't resolve (no legal target)
• The draw 2 effect doesn't resolve (no legal target means no controller to reference)

Nuances:

• If the unit were saved by Zhonya's or similar effects instead, it would remain a legal target and the controller would still draw 2 cards (even though the unit doesn't actually die, as the death is replaced)
• The unit doesn't need to die for the draw to happen, but it does need to remain a legal target