It can happen, but it’s hard to imagine that it could change the outcome.
Generally speaking, the parties send a slate of names to be electors. If Trump wins a state, the electors sent by the GOP are sent to Washington. If Harris wins, the Dem electors are sent. Many (not all) states outlaw faithless electors.
When it does occasionally happen, it’s a useless vote that wouldn’t have changed anything anyway. For a group of party loyalists to all work together to flip the outcome would be … unimaginable, frankly.
That cat has a quest for you.
Probably involving fetching some treats.