This is yet another horror film from the people who gave you Evil Winnie the Pooh, Evil Peter Pan, Evil Pinocchio, and other cheapo slasher characters designed to ruin your childhood. Disney must love these guys.
The copyright just expired on the pioneering animation Steamboat Willie, which kinda-sorta placed Mickey Mouse in the public domain, but only in this particular avatar.
The producers seem to have missed a beat by not calling this Screamboat Willie.
Atlanta also whipped out the plastic fantastics in another childhood-ruining film, Popeye, the Slayer Man.
There was another competing Steamboat Willie horror film, made/released around the same time, that called itself “Screamboat.” So, I think it was less of a missed opportunity and more of an intentional choice.