Why won't my Minecraft Grinch summon command work?

My friends and I are building a Christmas themed adventure map and one of the 5 challenges is a Grinch battle. It is a Zombie with an invisible guardian on top and the head of a monster. The Guardian and Zombie both have loads of Attributes. In the command block I put:

/summon Guardian 57 68 381 {ActiveEffects:[0:{Id:14,Duration:9999999,Amplifier:1,ShowParticles:0}],Attributes:[{Name:generic.maxHealth,Base:200},{Name:generic.attackDamage,Base:10}], Riding:{id:Zombie, Attributes:[{Name:generic.maxHealth,Base:200},{Name:generic.movementSpeed,Base:0.2},{Name:generic.attackDamage,Base:10}],{CustomName:Boss,CustomNameVisible:1,Attributes:[{},{},{}],Equipment:[{},{},{},{},{id:skull,Damage:3,tag:{SkullOwner:MHF_Blaze}}],CustomName:Grinch,CustomNameVisible:1}}}

It should in theory work but it doesn't in the bottom of the command block it says this:

Data tag parsing failed: Unable to locate name/value separator for string: {CustomName:Boss,CustomNameVisible:1,Attributes:[{},{},{}],Equipment:[{},{},{},{},{id:skull,Damage:3,tag:{SkullOwner:MHF_Blaze}}],CustomName:Grinch,CustomNameVisible:1}

Please can someone help!

minecraft-java-edition minecraft-commands

Best Answer

There are superfluous curly braces ({}) around the erroneous string. Remove those. Also, you specify the Zombie's CustomName and CustomNameVisible twice.

When facing data tag syntax problems, it is often helpful to explode the view in a suitable text editor that supports syntax highlighting, such as Notepad++.

Riding:
{
    id:Zombie, 
    Attributes:[
    {
        Name:generic.maxHealth,
        Base:200
    },{
        Name:generic.movementSpeed,
        Base:0.2
    },{
        Name:generic.attackDamage,
        Base:10
    }],
    {
        CustomName:Boss,
        CustomNameVisible:1,
        Attributes:[{},{},{}],
        Equipment:[{},{},{},{},{id:skull,Damage:3,tag:{SkullOwner:MHF_Blaze}}],
        CustomName:Grinch,
        CustomNameVisible:1
    }
}

You can easily see that after closing Attributes, you start a compound tag (open curly braces), but there's no tag to assign this value. Remove these braces, and CustomName: ... is correctly the same level as id and Attributes.