This article lists the interactions between Eraser and Snowball.
In BFDI, Eraser and Snowball were very close friends and both were very close with Pen. However, in TPOT, Eraser and Snowball had several conflicts during competitions but seem to be on better terms after the team swap.
In "The Worst Day of Black Hole's Life", Eraser constantly knocks down Snowball's stack, but despite being told to kill him twice by Bell, Snowball seemingly refuses to kill him and tries to stack his blocks again. It is unknown if Snowball didn't kill Eraser because they were friends, he couldn't get up, or Snowball just didn't feel like doing it and just wanted to stack blocks.
In "What's Up Bell's String?", when Eraser greets Snowball on his new team, him and Grassy greet him back, reaffirming their previous friendly relationship in season 1. Later when Snowball and his team go to retrieve Ice Cube, he tells Eraser to protect their pit.
In "I SAID CAREFUL!!!", Snowball is one of the people who wants to protect Eraser from going missing the most, picking him up and saying he needs to be kept safe.
In "Lofty", Eraser angrily asks Snowball why he popped Pencil's balloon, Snowball says it was because their balloons are pink and pink is too girly. Eraser disagrees with him and states that pink is quite "manly".
In "Today's Very Special Episode", Snowball says he can punch Eraser off of Bell's string. However, this was likely not aimed at Eraser, as other people have started climbing her string before Snowball arrived.
In "What's Up Bell's String?", near the end of the challenge, Snowball throws Eraser, along with four other contestants, down his pit to win the challenge, killing them all.
Non-canon[]
In "Thanks for 700,000 subscribers!", Snowball asks Eraser and Pen if they agree with him not caring about X spinning and they do so. Later, Pen, Eraser and Snowball looks at Six in the sky and Eraser asks if the three of them should tell Four, on which Pen disagrees and says to let it go. Snowball then sings "Let It Go", and Eraser and Pen both glare at him. He apologizes and states that movie meant a lot to him.