I try to understand you, because my English is not very good, so will use the translation software to reply you.
From my own understanding, you want to make a will explode with damage, that doesn’t destroy the environment, or do you want to make the original CREEPER indestructible. If you want to make a CREEPER like this, you need to write Lua, which can be modified directly after a CREEPER’s Lua copy, but not directly in the original. You can see that line 35 in Lua contains code that creates explosions, and you can look it up and see that the last two true’s are the cause of the damage to the environment. Just change it to false. If you don’t want to write a new one, you’ll have to type this command into the server:/safeflow-on
But if you’re in single player mode, you can’t use this command. If there is any mistake, please forgive me
In addition, I tried to modify the original Lua, the result is unable to enter the game
我试着去理解你的意思，但因为我的英文不是很好，所以会用翻译软件去回复你
就我自己的理解来看，你是想要制作一只会爆炸带有伤害，但不会破坏环境的爬行者，还是说想要让原版的爬行者变得无法破坏方块。
如果你想要制作一只这样的爬行者，就需要写lua，可以直接在爬行者的lua复制后修改，但请不要直接在原版里面修改。可以发现在lua里面的第35行有制造爆炸的代码，通过查阅可以知道，后面的两个true就是破坏环境的原因。只需要修改成false即可。
如果你不想重新写一个，就必须要在服务器中输入这个指令：/safeblow-on 但如果你是单人模式，就无法使用这个指令。
如果有错误，还请见谅
另外，我试着去修改原版的lua，结果是无法进入游戏
