This has happened on each of my last three runs.
[66] Guano Junction
Encounter: vampire bat
You acquire an item: sonar-in-a-biscuit
[70] Guano Junction
Encounter: doughbat
You acquire an item: sonar-in-a-biscuit
[72] Guano Junction
Encounter: doughbat
You acquire an item: sonar-in-a-biscuit
> use 3 sonar
You need 1 more sonar-in-a-biscuit to continue.
> inv sonar
sonar-in-a-biscuit (2)
> refresh inventory
Refreshing closet...
Updating consumable items...
Updating miscellaneous items...
Refreshing stickers...
Requests complete.
> inv sonar
sonar-in-a-biscuit (3)
[66] Guano Junction
Encounter: vampire bat
You acquire an item: sonar-in-a-biscuit
[70] Guano Junction
Encounter: doughbat
You acquire an item: sonar-in-a-biscuit
[72] Guano Junction
Encounter: doughbat
You acquire an item: sonar-in-a-biscuit
> use 3 sonar
You need 1 more sonar-in-a-biscuit to continue.
> inv sonar
sonar-in-a-biscuit (2)
> refresh inventory
Refreshing closet...
Updating consumable items...
Updating miscellaneous items...
Refreshing stickers...
Requests complete.
> inv sonar
sonar-in-a-biscuit (3)