When entering travel mode, my baby spiders despawn.
#Baby spiders despawn when entering fast travel.
leaden zenith
last fossil
The spiders are your babies, and take quite a while to hatch, which makes this rather inconvenient. Same happens with the BC golem. It's irritating when soloing, but especially when in a party doing overland content when I can't summon as someone else is in combat.
snow ermine
Necro zombies do the same thing.