If it's a land, it goes directly into your hand
Notably, this means that no player can respond to remove your Dragon before the cost is reduced, and if you sacrifice that Dragon as part of a mana ability, the cost won't be increased
The question is always how far you take it
You can get a Sliprider for a quick Spell/Trap destruction, a Strawman to push for a lot of damage, a Soartroopers if you already setup a graveyard Psychic-type Kozmo monster (typical Dark Lady), get a Farmgirl if the opponent has an open field, theres a lot that can be done and its all mostly situational
Sure, you can go in a Hydra kindred direction, which is probably the most straightforward way to go, but you can also go for a big burn spell deck or a ramp deck