Damage doesn't reduce a creature's toughness, so that won't work, but a -X/-X effect or an accumulation of -1/-1 counters do the trick
But there are reasons as to why people keep doing it, and that's what I'm here to talk about with you today
If a token is exiled, it ceases to exist
While somewhat difficult to get into play, fusing these two creatures will all but close a game out for you
Those tokens have "Sacrifice this token: Add ." Creature - Eldrazi Wastescape Battlemage Kicker and/or When you cast this spell, if it was kicked with its kicker, exile target artifact or enchantment an opponent controls
MTG has always been pretty tied to Dungeons & Dragons , and if this was a representation of a campaign then the legendary creatures would be the protagonists or enemies of said campaign