Pokemon Co. was very adamant about one rule for the team making Detective Pikachu. All Pokemon had to remain adorable, no matter what. This posed quite a challenge for specific Pokemon, none moreso than Lickitung. In an interview with i09, Pete Dionne, a VFX Supervisor on the movie, discussed the work that went into Lickitung's tongue.
“It feels like a baby’s tongue. Ultimately, what we ended up using was a giant, scaled-up baby’s tongue, with the same very soft, but slightly coarse texture, with the slightest level of moisture. And trust me when I say a lot of discussion went into that.
The first proposal was that [Lickitung] wouldn’t even have any saliva. Saliva is too gross. It would just be a completely dry, soft silicone tongue, which, you know, wasn’t going to work for the whole gag. So there was endless amounts of finding, ‘In nature, what is the cutest version of a tongue?’ and then finding reams of reference for that. That was kind of our design process, across the board.”