ABSOLUTELY NOT. DO NOT DO THIS.

You are talking about making a suicide cord. I repeat: DO. NOT. DO. THIS.

Your best bet is to simply tap the circuit that feeds the light, and run Romex to a new receptacle. If you MUST feed from a live outlet with an extension cord, use the appropriate power inlet receptacle.

I would think using a Power Inlet Receptacle would make it legal.

What happens is that you have an exposed electrical shock/short/fire hazard. As an alternative you could wire a short male cable to your workbench, or even install a power inlet: https://www.amazon.com/Leviton-5278-CWP-Straight-Flanged-Receptacle/dp/B003ATXIBG

I put one in my living room for the TV a few years ago. I'm pretty sure I put it in a standard box. Maybe more like this one: https://www.amazon.com/Midlite-MDT4642W-Single-Gang-Decor-Recessed/dp/B002XDQAA6/ref=pd_sbs_263_3?_encoding=UTF8&psc=1&refRID=C1HVSTSPE9PSYE5ZTKQE

They also sell outdoor ones: https://www.amazon.com/Leviton-5278-CWP-Receptacle-Industrial-Grounding/dp/B003ATXIBG/ref=pd_sbs_263_2?_encoding=UTF8&psc=1&refRID=C1HVSTSPE9PSYE5ZTKQE

Edit: oops, looks like u/cryo_burned beat me to it.

Okay looking into it some more, I think you’ll be fine daisy-chaining. The bridge plate on a 15A receptacle should be able to handle that.

In home wiring there can be tails wire-nutted in each junction box so one receptacle can be removed without breaking the circuit.

I’m not sure if there would be an issue using stranded wire in the outlet screw terminals. What I would make sure of is that your cord is anchored in some way, so pulling on the extension cord isn’t putting force directly on the screw terminals.

Again, if you search for power inlet receptacle like so , you can avoid that whole male cord issue.

Something like this in your ceiling?
https://www.amazon.com/Leviton-5278-CWP-Receptacle-Industrial-Grounding/dp/B003ATXIBG/ref=sr_1_13?s=hi&ie=UTF8&qid=1468333722&sr=1-13&keywords=Electrical+male+inlet