Could be the Neomorph? Slight variations between the two. We see security forces fighting the Neos in the trailer so perhaps.
he clearly mentiones the xenomorph, so no.
also, why not, the saliva? i can't remember seeing their saliva in contact with human tissue. it doesn't HAVE to be acidic, though
offcourse it does sound like that. Perhaps not as strong as the acidic blood, but comparable.
for example, saliva of a komodo dragon is highly toxic. the gila monster produces toxic saliva.offcourse the komodo dragon has bacterial effects, rather than 'burn'. but well, if it is acidic in nature, it definately can burn.but let's just take diesel oil for example. i've had a bit on my jeans at the upper leg area when fueling and slipping when the floor was ice frozen. i didn't think much of it, and thougt hey, i'm home in half an hour, i'll wash it off then.
unfortunately, when i got home, my skin was superbly irritated and had a strong red rash, which lasted about a day and a half.
so, here you have 'simple' diesel, which thus 'burns' the skin somewhat.so i can imagine alien salive of a dangerous creature having a stronger effect though.