Plan ahead

Remove known triggers from the area, things that have caused previous issues.
Teach the differences between tantrums and meltdowns and how to react to each.
Train how to get out of holds and grabs.
Assign volunteers to guard exits and escape routes.
Create and practice a plan to find a lost child.
Consider asking parents of children who like to undress, to have them wear one-piece garments or something more difficult to remove.

Either move an aggressive student to a secluded area or move other students away.
Place distance between you and the student. Stand near an exit or just outside the room where you can still observe.
Tie back your hair, remove accessories that can be grabbed, cover exposed arms, or use Kevlar sleeves.
Remove nearby items that may be thrown or used to poke; remove shoes from kickers.
Try not to grab or hold the student, unless it's necessary for their safety.

Have someone give you a break or try something different. Students may respond well to different people or ideas.
Continue to let the student know you care and want to help. Ask the student for their advice and help to resolve the situation.
Try silence and allow time to calm the situation, especially when talking seems to make it worse.

Whether you call in the parents for help or give them an update at pick-up time, make sure they know their child is still loved and welcome to return.
Review the situation with the volunteers involved to calm concerns and offer ways to support them as they continue serving.
Report the incident in accordance with your church's policies, recap the situation with your team, and plan to prevent recurrence.