So should I have my doubts about whether I´d be happy to meet these snakes in Singapore?
For sure this is their habitat, so yes, welcome spitting cobra! We must understand that we are the invaders in their living room, and snakes play a very important role in nature. They feed on rats, mice, and amphibians, so they help to control the population of such species.
Once you found the first, you are likely to find others every now and then. They can appear right next to you, usually in the grass. And they are very impressive, maybe the most impressive snake I ever met. Jet black, with a large head and a serious expression on their face. Perhaps my impression is stained by the knowledge of their potential venom and the ability to spray it into your eyes. So the best you can do when you see a black snake right next to you: keep breathing, don’t move, and watch it going its way. They won’t stay close to you, or would you stay close to a giant that could step onto you? No need to take any action! 15 out of 29 species of cobras have the ability to spit venom and this venom can damage your eyes.
The word naja made me curious. This article mentions the usefulness of a subgenus, which I heard first when reading about the cotton-stainer bug! It says naja is from the Sinhala language and is the word for cobra. As simple as that.
Naja sumatrana 
Naja sumatrana
English 
Deutsch