Borderlands - Mighty Morpin Problems; Mutant Badass Varkid lost

Sir Hammerlock provided me with the injector, and when I injected the pod, this huge green badass thing popped out and killed me. Now I cannot find it, nor can I inject another pod to achieve the same result. The quest is still active asking me to kill the mutated varkid but it is no where to be found. What am I to do?

You can make more Mutated Badass Varkids; just inject another pod by using the Action key (E on PC). For this, there is no action prompt, but you can still do it. As soon as the pod hatches, you will know if it worked. Just get as close as you can and press E/pick up a couple of times. After trying to "inject" a pod, prepare to face a Mutated Badass Varkid immediately if it works. Fire is weak to them, and they deal Corrosive damage.

If you want to speed up the process, you can also spawn multiple mutant badass varkids at once. If you aren't significantly overleveled for the quest (I assume you aren't), I strongly advise against doing that.

To make more mutants and kill them, you'll have to do it several times. Even if it's awkward, you can still hatch multiple mutant Varkids, unless you've caught a glitch. The one you made before does not need to be found (he has despawned by now).