This is gonna be a Riley rebus suggested by @Duck (Thanks)
Be sure to check out some of his great riddles and puzzles like this and this :D
Note :
I will probably (Definitely) post another one of these. It's here :D
Will also add hints if nobody gets if after a while
Small Hint :
Don't take things too literally
Another Small Hint :
The Suffix picture is a game called agario
Specific Hint for Prefix :
It's a way of measuring something that is also related to a circle