Polyp or manjano?

[Snooch2thenooch]

Set up a tank and these came with the live rock. The worker told me they were polyps however im not so sure. Possibly manjano? Theres a few of them on the rock varying in sizes. If its a pest I want to get ahead of it! Tia

 

[bradleym]

Looks like majanos to me.

 

[D.WhiteShark]

+1 look like Majanos. If it's only on one rock, I wouldn't risk it. Pull that rock. Replace with another piece. Even if the new piece is not "live rock" it won't take long for the good bacteria to turn it into live rock.