Puniru wa Kawaii Slime

Cute supernatural girl comedy. While Ika Musume is a squid and Puniru is a slime, both have the appearance of a cute girl and are unique beings (in an otherwise normal world) with supernatural abilities that can wreak havoc and cause laughter in a charming slice of life comedy. 

Similarities: -Both anime are comedies with a protagonist reluctant to give in his feelings to a non-human girl. -Most episodes revolve around Puniru and Lum trying to convince the male protagonist to notice them. Differences: -Puniru is oblivious to romantic feelings and Lum isn't. -Kotarou is not a pervert like Ataru. 

They are similar animes in terms of being nosense and having supernatural beings altering what happens to the characters.  

Both are about a boy with traditionally feminine interests, who faced backlash because of it. Though Puniru is a comedy and Senpai wa Otokonoko is a drama, making them different in tone, both are very positive in their messages that it’s okay to like whatever you like.