Butterfly
A butterfly with another butterfly added to it? It's still a butterfly, just a really big one with... with four wings. And laser eyes? Oh well, just go with it. It's a butterfly.
ちょうちょう
The reading is just the on'yomi readings (which you learned with the kanji) twice in a row.
彼女は蝶々のように自由な女性でした。
She was a woman who was as free as a butterfly.