When Deadbloom Predator is played to the battlefield, does it immediately trigger combat, or can you simultaneously move other units from base to battlefield?

Ruling: Playing Deadbloom Predator to the battlefield starts a showdown right away. There is no opportunity to move other units with its summon.

Sequence:

• Deadbloom Predator is played to battlefield
• Showdown begins immediately
• No window to move other units from base to battlefield