Okay, you seem oblivious, so let me break it down for you. The ball of corn is a reaction image, a "cornball". A cornball is one who acts corny, often making others uncomfortable. Sarcasm; Sarcasm is a literary device meaning the opposite of what is said. In a context such as, "nice username" followed by the "cornball" image, the phrase "nice username" is used sarcastically. And the "cornball" image is used to insinuate that the username of the person targeted by the remark is 'corny'. In this context, I have called your username 'corny'. As in it hurts to read, 'overly dramatic' and 'cringy'; I'd be happy to explain the meaning of any other literary devices and/or pop-culture phrases to you:)
'sarcasm' can also be hinted at by phrases such as 'gng' 'cuh' 'twin' and 'bro'. In this case slang 'gng' was used, 'gng' is a contraction for the word 'gang', having a similar meaning to 'dude' or 'bro'. Saying 'gng' in a seemingly weird context can make it apparent to others that the message is meant to be interpreted as a joke or satirical remark.