These peculiar forms not only seemed designed to shock people emotionally, but to give them electronic shocks as well!

【翻译】这些奇特的造型，看起来故意设计的不仅要给人以情感上的震撼，而且还要给人以电子冲击。

很简单：seemed 是系动词，意为“看起来，似乎是”；designed 是形容词作表语，意为“特意的；故意的”。

后面两个不定式表示“目的状语”。