I had seen some cool custom toxins but my favorite ones were the first form. I do have the actual toxin toy but I like spider-man build compared to the venom one. So I grabbed a black spider-man painted his upper half red and his lower half black. then I used a silver paint pen for the eyes rather than sculpting them. Then I dremeled his fingers off and hot glued floss pick ends in place then super glued them to keep them from falling off and painted his hands black. After all that I hot glued symbiote veins on his torso legs and arms and painted those red.
*Update*
So I finally got around to sculpting his jaw. I made it with green stuff and then after it dried and I painted it and everything I tore it off and added a tiny magnet to make it removable. I also tore off the hot glue symbiote veins and painted them on just because I thought it looked cleaner.