Use their own weapons against them.
Avatar is a registered trademark in the USA, owned for various classes by various companies.
Among others, IC 009. US 021 023 026 036 038. G & S: Computer software for the generation of web based computer programs and instruction manuals / IC 042. US 100 101. G & S: Business technology software consultation services are owned by iRise CORPORATION CALIFORNIA.
It may be worth pointing iRise corp to the derogatory and damaging use of their trade mark by a "computer programs" and "software consultation services" type of company. It doesn't cost you more than a letter.