Apparently Pharrell tried to set up a YouTube channel called "I Am Other" and then sent him a cease and desist because he thinks that HE OWNS THE RIGHTS TO EVERYTHING WITH AN "I AM" IN IT.

Pharrell didn't run scared … he ran to court … and SUED Will — in an effort to stop Will from stopping him.

In the suit, filed in federal court in NY and obtained by TMZ, Pharrell argues that they are each using "I Am" in completely different ways. Pharrell says Will is using the "I Am" is a Seussian way — as a playfull riff on his own name — and to hammer home his point, he quotes from Green Eggs and Ham: "Sam I am I am Sam I am Sam Sam I am"

Pharrell continues in his suit, "In contrast, the I Am Other mark means 'I am something else,' leaving what that 'else' is to the imagination of the consumer. It certainly does not mean 'I am Will.'"