How do you wow second-year students into saying "bare-metal programming is cool!"?
First, just a disambiguation: are you teaching Assembly language or C? Cos, they are not same as your question seems to suggest. C is a high-level procedural clean code language with tremendous abilities to speak to the bare metal similar to but not as Assembler pls. It may help you bridge to assembly but it is not assembly. Let that be clear to your students.

Never taught machine programming/ASM. But your question touches something in me: the need to wow! the student; I have same predilection with students. So I felt obliged &amp; did some talking with friends in the know and some research. 

Here’s the widow’s mite I pieced together. Hope it helps:
You can add the following to your first lab “sales pitch’:


Let the first lab be a NO CODE, no Technical stuff class. Just getting familiar with selves and ASM in a general way with nothing too technical and thus “intimidating” or “off-putting”. The class should be (pardon my cliché): sugar and spice and all things nice. Toward this:
Add to your spiel, a history of Assembly telling them of Kathleen Booth &amp; others etc. Make it interesting. Search &amp; find some spectacular successes and exploits using ASM and also some disasters of sloppy ASM. Apart from sparking interest and discussion, the last part will have the additional pedagogic value of sensitising the students to their power as oracles speaking to the small dumb “god” in the machine. Also it will put them on notice of the enormous responsibilities their heightened power as bare metal oracles imposes on them to avoid sloppy code (not only for ASM but programming generally).
Let the students see how the higher level languages with their swagger and leaky algorithms are actually, mostly dependent on ASM and C. Let them see that a lot of our higher level constructs e.g. macro were borrowed from Assembler.
As @Buffy I. rightly pointed out, talk alone can’t win a non-committal or skeptical mind. To give them something interesting: show them some good things (e.g. games) made in Assembler and display for them on slide (s) the assembly code snippets that made such things. In this regard I found some of these online and hope they may help or stimulate some interesting ideas:
https://spectrum.ieee.org/geek-life/reviews/three-computer-games-that-make-assembly-language-fun.amp.html


https://www.quora.com/What-are-some-cool-assembly-language-projects-I-can-do?top_ans=21546329

https://brianslam.wordpress.com/2014/04/06/assembly-is-fun-sort-of/

https://news.ycombinator.com/item?id=16710543

This one is a Compendium of Assembly Coding Practices from Coding Project. It may help illuminate your teaching:
https://www.codeproject.com/Articles/1116188/40-Basic-Practices-in-Assembly-Language-Programmin