The hive invading skeleton is a skeleton invaded by the hive, that is, infected. It can shoot hive infection projectiles. It can merge with other skeletons to become a more powerful entity. The fusions are:
Hive invading skeleton + Hive invading skeleton = hive silencer.
hive invading skeleton + silencer = hive breastbone.
hive invading skeleton + hive breastbone = hive vertebra.
It has two variants; the normal one and the yellow one. The normal one is when a skeleton is infected. The yellow one is when it is summoned manually by the hive.