The Venom symbiote could improve Strength, Blunt and Hand to hand. Where Carnage could improve Blade, Agility and light armour (The symbiotes in spiderman suffer from loud constant noise blasts and heat) so all symbiote forms suffer a 100% fire and lightning damage And have a toggle spell to switch back and forth to your normal forms. So when in human form all bonus abilities and Penalties, But in Symbiote form, The Bonus and Penalties return.