Creating something like the mini bosses from fortnite save the world

Hello, as a simple test I’ve tried to create the STW bosses, but I’m just unsure as to where to start. For anyone unfamiliar with the game, bosses (or, as they’re called, minibosses) are enemies that spawn with specific modifiers (i.e vampiric, tank, frenzied).

I’m not here to ask for a script, but what i need most is just a basis. I can work from there.

-Cheers, 80s.