Copyright: cheesed to meet you
"Cheesed to meet you" is a meme that originated from 4chan and was popularized on Tumblr and Twitter. The phrase (and grammatical variations thereof) is a pun on the phrase "pleased to meet you" that plays upon the stereotype of cheese being loved by rodents, namely mice and rats.
The phrase was first used in this context in August 2019 in a thread on 4chan's /tv/ board. The thread, starting with a rendition of Apu Apustaja as a hissing domestic cat, was responded to with "SMALLRATPEPE" (a 2018 image of Pepe the Frog as a rodent) with the text "Uhm, cheesed to meet you?"
It wasn't until next August when a screenshot of the interaction was reposted to Twitter by user @woodsyowle and later to Tumblr by themysteriousmurasamecastle, leading the phrase to gain popularity. Artists would broaden the meme beyond SMALLRATPEPE, adding it as captions to mice and rats in general.
themysteriousmurasamecastle: obsessed obsessed obsessed obsessed to death with this image
KnowYourMeme page on the subject