It’s called SM-102.
Verifying that it is in the Moderna COVID vaccine, I find a 12/30/20 CDC document titled: “COVID-19 Vaccines: Update on Allergic Reactions, Contraindications, and Precautions.” 
If you scroll down halfway through the document, you’ll see a chart titled, “Ingredients Included in mRNA COVID vaccines.” (pg 20)
The right-hand side of the chart shows ingredients in the Moderna vaccine. The fifth ingredient down is “SM-102: heptadecan-9-yl 8-((2-hydroxyethyl) (6-oxo-6-(undecyloxy) hexyl) amino) octanoate.”
Now we go to a document published by the Cayman Chemical Company of Ann Arbor, Michigan: “Safety Data Sheet acc. to OSHA HCS.” (04/11/2021) 
This data sheet lists the effects of SM-102. Here is the opening note: “For research use only, not for human or veterinary use.”
Far from comforting.
Then the safety data sheet lights up with adverse effects/warnings re SM-102. For example: “Suspected of causing cancer. Suspected of damaging fertility or the unborn child. Causes damage to the central nervous system, the kidneys, the liver and the respiratory system through prolonged or repeated exposure. Very toxic to aquatic life with long lasting effects.”
Several things to point out here. First, what dosage level of, and what duration of exposure to, SM-102 are we talking about? Details on these toxicity factors need to be known. HOWEVER, all that is overridden by the fact that SM-102 is being INJECTED into the body via the Moderna shot. We’re not just talking about inhalation or skin contact.
Obviously, the human body has layers of defense against attack. With injection, a number of those layers are bypassed.
And once deep within the body, where does SM-102 travel as it causes damage along the way?
I doubt that the Cayman safety data sheet even considered the possibility that SM-102 would be injected.
The experts and authorities will assure us SM-102 is safe. They’ll say only miniscule amounts are being injected. They’ll say the clinical trials of the vaccine revealed no problems. They’ll parrot, over and over again, as they always do: “safe and effective.”
You’re walking along a country path. You see a snake lying just ahead of you. He slowly raises his head and looks at you. On his hood, you read the words: “emergency use authorization granted.”
SOURCES: https://emergency.cdc.gov/coca/ppt/2020/dec-30-coca-call.pdf [1b] https://www.youtube.com/watch?v=9RcgAXSKQyw [1b1] https://youtu.be/9RcgAXSKQyw?t=638 [1b2] https://youtu.be/9RcgAXSKQyw?t=840  https://www.caymanchem.com/msdss/33474m.pdf