In this rule

Historical Rules · 13 October 2023

Rule 701.37c

Official source text from the 13 October 2023 Rules release

Permalink

If an effect instructs a player to meld objects that can’t be melded, they stay in their current zone. Example: A player owns and controls Midnight Scavengers and a token that’s a copy of Graf Rats. At the beginning of combat, both are exiled but can’t be melded. Midnight Scavengers remains exiled and the exiled token ceases to exist.

Find this number in the current Rules