"雷人" means shock, It's informal language and original from online chat. Additionally, it's adjective and describe someone or something is shock,surprise,amazing

*The common using:
1. 这件事太雷人了。
This thing is so supprised.
2. 你太雷人了
You are so amazing
3. 你雷着我了
You shock me
4. 天雷滚滚~
Really shock.