Ok this is just for fun im not telling you how to actually create your own symbiote ;)
all you have to do is list the details of your symbiote such as:
Name:
Description/Appearance:
Abilitys:
Host:   (made up or from the marvel universe)
Origin:
Have fun ;) 
 

Name: Claw.
Look: A Grey Symbiote With Elephant Tusks & Orange Spikes On It.
Powers: Due To Having Three Past Hosts With Powers (Wolverine, Doctor Strange, & Namor), He Has All Their Powers. After Finding His Current Host (War Machine), He Has All The Armor's Weapons. Like All Symbiotes, He Has Spider-Man's Powers. A Signature Power Claw Has Is The Ability To Sprout Orange Spikes From His Body. The Spikes Can Inject A Poison That Is Deadly And Can Bypass Wolverine's Healing Factor. His Claws Are Also Tipped With The Poison.
Host: (Former Hosts) Wolverine, Doctor Strange, & Namor. (Current Host) James Rhodes, Formerly War Machine.
Origin: Claw Is The Son Of Agony.
Claw Is An Enemy Of Wolverine.

name: Slaughter 
look: similar to carnage only a lot bigger and green 
powers: super human strength that increases with his anger, rapid healing factor, the usual spiderman abilities, is immune to sonics and fire, 
host: world breaker Hulk 
He's a world wide threat

" name: Slaughter look: similar to carnage only a lot bigger and green powers: super human strength that increases with his anger, rapid healing factor, the usual spiderman abilities, is immune to sonics and fire, host: world breaker Hulk He's a world wide threat "

There is a thread for this already.