Like the other 2 installments of the series, Beyond Re-Animator begins and ends with excessive grossness. In the positively ghastly opening sequence, a young boy helplessly watches his sister being strangled to death by a walking corpse with no mandible.
Flash forward - Dr. West has had 14 years in prison to reflect upon the deadly consequences of his mad science. He concludes that he was right all along and his indignant disposition hasn't changed even slightly. If anything, he's more determined than ever to continue his research in reanimating the dead. In prison he's forced to endure abuse from the other inmates as well as the crusty old warden who is hell-bent on making everyone around as miserable as he is.
Hope arrives in the form of a newly assigned prison doctor. It is soon revealed that this doctor has closely followed West's career as he is none other than the child I spoke of in the 2nd sentence. It is he who supplies West with his favorite thing in the whole wide world - a syringe full of the neon juice! It takes Dr. West 35 seconds (I timed it) from the moment he's handed the syringe to the moment he injects a dead body with it. This includes time taken out to contemplate and respond to the question "what are you doing!?" Lo and behold, said corpse awakens and becomes an uncontrollable frothing monster prone to fits of extreme violence.
Everything quickly spirals out of control as they tend to do in this series. The warden gets his mitts on the juice and uses it to revive criminals who got off too easy with the death penalty for the sole purpose of furthering their suffering. By the time the credits roll, you'll have witnessed a prison riot, an exploding druggie who shot the stuff into his veins, and most distressingly, a penis being bitten off, spit out, and carried away by a mouse. Try having a nice day after that one.
What seemed like an unnecessary, ill-conceived idea managed to overcome the odds and become another amusing, worthwhile addition to the madness.