Mantis Ootheca

An ootheca is a type of egg mass made usually by insects or mollusks.
The word is a Latinized combination of oo-, meaning "egg", from the Greek word ōon (cf. Latin ovum), and theca, meaning a "cover" or "container", from the Greek theke. Ootheke is Greek for ovary.
An ootheca usually contains many eggs surrounded by a foam of protein which may then harden into a tough casing for protection.