Can you react to flip a hidden Teemo before a Temporary Sprite disappears at the beginning of your turn phase, or can reactions only be used on opponent's turn?

Ruling: You can react before the Temporary Sprite disappears. Temporary is a triggered ability that uses the stack, allowing you to respond to it by flipping Teemo before the Sprite is removed.

Nuances:

• Reactions can be used on your own turn, not just on the opponent's turn
• The Temporary trigger goes on the stack during your turn's ABCD steps, creating a window to respond