Fishliver Oil is a very cheap card to play so you can play it when you want to
Casting a spell gives each player a chance to respond to it before it resolves, in turn order
Guardian Beast was the next time this destruction-proof keyword was seen, in Arabian Nights later that same year
It doesn't have any downsides, and it doesn't even have activation restrictions, so if you want to make the most of his Numeron monster's own effect directly, this is also a must-have effect
Recurrent neural networks are especially good for sequence prediction tasks, and theyre the go-to model for many language tasks (see The Unreasonable Effectiveness of Recurrent Neural Networks)
Because we didn't always have access to multicolor (this was back in the day where we wouldn't put multicolor cards in sets without a multicolor theme), we decided the ability made the most sense in black