Found this structure in the hypha of a species of Hymenochaete. It was quite frequent in the context. Is it common for such structure to appear? if yes, than can someone please provide me the reference.
It is possibly some type of resting spore like a chlamydospore.
From wiki: "Chlamydospores are usually dark-coloured, spherical, and have a smooth (non-ornamented) surface. They are multicellular, with cells connected by pores in the septae between cells."
Page 11 in this pub has a nice drawing of chlamydospore and other morphological features. https://link.springer.com/content/pdf/10.1007/BF02055052.pdf