On July 20th, an individual in California (apparently the individual behind the Instagram account), filed an application to register LIL MAYO as a trademark with the USPTO. The individual filed the application in two classes - 35 and 41 - for the following services:
(35) Endorsement services, namely, promoting the goods and services of others; (41) Entertainment services, namely, personal appearances by a fictitious alien character, Lil Mayo; Fashion modeling for entertainment purposes; Entertainment services in the nature of live visual and audio performances by a fictitious alien character, Lil MayoAccording to the application, LIL MAYO has been used as a trademark in conjunction with these services since April 21, 2015.
Side note - typically the USPTO does not favor an applicant using its own trademark in the identification of goods and services (LIL MAYO, in this case), so the applicant may be required to delete "LIL MAYO" from the identification of services before this mark can register (assuming there are no other issues). TMEP 1402.09.
Earlier this year, the same individual that filed this application filed another application for LIL MAYO covering "t-shirts." However, the USPTO issued an Office action refusing to register that trademark due to a likelihood of confusion with an existing registration for MAYO owned by the Mayo Foundation for Medical Education and Research that also covers various clothing items, including t-shirts. The applicant will have a chance to respond to the refusal, but has not yet done so.
Additionally, this individual owns a pending application for the alien head logo seen below that covers "hats" and "t-shirts." That application will be published for opposition on August 14, 2018 - the final phase of the registration process for a trademark that is already in use. See TMEP 1502.
Lil Mayo Instagram account is a verified account with 1.8 million followers and consists primarily of photographs and videos of a little alien doing all sorts of wild stuff (as the Instagram post above from the account demonstrates).