I read a short story in an anthology when I was very young (I'm guessing it was some time in the mid-'70s). All I remember is that there was a blob-like alien of some kind, sitting in the middle of a city, shooting out tentacles that people would stick to, and be drawn into it, I assume to be digested.
Sounds vaguely similar to parts of "The Kraken Wakes" by John Wyndham. Aliens who live at high pressure invade the Earth's oceans, and send tanks on to the coastlines. These tanks shoot blobby tentacles that stick to people, drag them to the tank, and then the whole mass is drawn back into the water as the tank retreats with its captives. What happens to these unfortunates is never revealed.