Replacing a Witch's Familiar (GM)

I've been running Rusthenge for a party that includes two witches (which oddly works, somehow). One of the witches (Devourer of Decay) has had a familiar named Persephophone, which was a scrawny owl, using the raven statblock. Several times throughout the adventure the player has summoned her familiar to get into harm's way -- sending it onto a roof to scout out danger, sending it through a forcefield of sorts, and on two occasions, summoning it so that it could flank an enemy. Well, in yesterday's session she did just that -- summoned her owl to get behind a >!dero stalker!<, assuming that another PC would get into flanking position. They didn't, and so the owl was the only target within melee range of the >!dero!<...and it critted with a Nat 20 on its first hit. Even with the Phase Familiar reaction, and even with the special familiar rules on damage, the sheer amount of damage made it an insta-kill.

But as with all misfortunes in this game, I saw it as an opportunity. Familiars are replaced the next day by a witch's patron, and sometimes those familiars will be the same creature, and sometimes they'll be different, at the patron's (i.e. GM's) discretion. I chose to replace her owl with a Talking Head, who will have a never-ending quasi-sarcastic diatribe of exactly how the witch should be doing things. My player knows this will be tongue-in-cheek, with the slightest grain of truth buried in the humor.

So...since I'm sure many GMs have had the opportunity to replace their players' familiars, I'm curious: what were the circumstances, how did you approach the replacement, and how did it play out in the sessions that followed?