The entity UUID provided is in an invalid format
/kill @e[type:EnderDragon]
The entity UUID provided is in an invalid format
/kill @e[type:EnderDragon]
bug
(Unassigned)
Unconfirmed
Minecraft 1.9
Retrieved
You use a an equals sign to seperate 'type' and the specified entity, not a colon. That might be the issue.