% replaces any number of letters (la% - lake, lamp)_ replaces one letter (ca_ - car, cat)

Crossword clues for they pop up from time to time

AnswerClue
ADSThey pop up from time to time
SMILESOld-time pop ballad.
DROPINHOURSTimes to pop by, and a feature of the starred clues' answers (hint: include two letters below them)
SECADATwo-time Latin Pop Grammy winner Jon
MESTWasting Time pop-punkers
BTSBoy band dubbed the "Princes of Pop" by Time magazine in 2019
BTSGroup crowned "Princes of Pop" by Time magazine in 2019
THEOLDSOne's behind-the-times mom and pop, slangily
VIDEOSuper annoying pop-up, at times
VOX__ Pop (old-time radio show)
BTSBest-selling K-pop band of all time
SPIDERMANANDBOYGEORGELife time of comic hero with pop singer
TAYLORSWIFTCountry-pop star with the 2008 six-time platinum album "Fearless"
KASEMHis New York Times obit described him as a "wholesome voice of pop radio"
ROBERTINDIANAPop artist whose best-known image is replicated eight times in this grid
ROBERTINDIANAPop artist who created a famous verbal image in 1964 (reproduced four times in this grid)
LOVELANGUAGESQuality time, words of affirmation, receiving gifts, acts of service, and physical touch, per a 1992 pop-psychology classic