I'm from the "ask your parents" era so I may be able to lend a hand with some of the references. Thanks to
Ginny for posting the link
when talking to grandpa stinky he calls sam and max barney and harvey..... I couldn't get him to call Sam Barney. What he said to me was something like, "Have you ever hit anything with that gun of yours, Fido?"...
"
Barney" (Sam) would be Barney Fife, the deputy on The Andy Griffith Show. Barney was such a bad shot he was only allowed to carry a single bullet and even then he had to keep it in his shirt pocket. The few times Barney was actually able to fire his gun outside of the holster still resulted in his intended target being missed.
In the original 1950 Harvey movie, Elwood P. Dowd (played by Jimmy Stewart) said that Harvey was a "pooka". A pooka is an imaginary friend, just like Max.
And Harvey here is fine, until we reach a planet with a 'You must be this tall to invade' sign.
Looking at the screen shot, the scene is referring to the movie, Godzilla versus Mothra (1964). Mothra often did battle in Tokyo and when he/she/it died, the egg it tried to protect was left behind to hatch and carry on the butterfly-monster legacy. Max would be Godzilla and the pink creature is a Mothra during its larval stage (ergo, the need for the height requirement sign).
When you check out the ectoplasm on the table in Bosco-Tech Labs, I think there might be a Ghostbusters reference, but I could be wrong.
I'm 99% sure the Ghostbusters movie reference is right. Ectoplasm is believed to be physical evidence of a ghost or spirit so if the ghosts in the movie left slime behind, one would naturally expect Mama Bosco to ooze, too. My 1% doubt is due to the movie's release date (1984) which is 20-30 years later than the other "ask your parents" era references.
I hope this helps!