While unable to breathe underwater herself, Chrysalis grew quite accustomed to her new underwater hive, and decided to bring in some more ponies to feed on their love. If she could drown them, they wouldn’t struggle as much, and decided to steal Spike when he swam in her lake and dove into the cave.
 
With Twilight swimming with him and hot on their trail, Chrysalis only needed to bring her in and her changeling army can take care of her and drown her in a tangle of grapples, fists and kicks.
 
“Yougb wanb yougbr dragbon back? Comble geb himgbl!” She bubbled to the alicorn.