Does playing Elder Dragon initiate a Showdown?

Playing Elder Dragon itself does not initiate a showdown.

A showdown is initiated by game actions that make a battlefield "Contested" (Rule 344), typically when a player moves a unit to a battlefield occupied by an opponent's unit.

• Elder Dragon's Play: Playing a unit (including Elder Dragon) is a card play action, not a move action. While Elder Dragon has a "When you play me" triggered ability that deals damage to units at various locations, this ability does not create a contested battlefield status.
• Triggered Abilities: According to the game rules, triggering an ability does not inherently initiate a showdown.

If playing Elder Dragon causes a unit to move (for example, if a separate card effect were activated in response), that move could potentially lead to a showdown if it results in a battlefield becoming contested. However, simply playing the Elder Dragon card does not do so.