Parasite

(To be used only with my parasite race)

Parasitic host

You can attempt to merge with a living creature as an action 

Otherworldly physiology

Your otherworldly nature allows you to improve your host's traversal ability 

Hostile takeover

You can forcefully take your hosts body

Strengthened bond

You can now mask your host to gain extraordinary benefits 

Symbiosis

You and your host perfectly understand each other and can now fight side by side