Rubbery bulb

Stretch Plants are a species of plant appearing in the game Super Mario Galaxy and Super Mario Galaxy 2. They appear as green plants with a bulbous head and a thin, stretchy stem.

Super Mario Galaxy
In Super Mario Galaxy, Stretch Plants appear in various galaxies, most notably the Good Egg Galaxy. If Mario or Luigi Star Spin one, it will stretch in the opposite direction, hitting any obstacle in the way. If it fails to hit an obstacle or an enemy, it will come right back and hit the plumber, causing them to fall back and lose some Star Bits. If one is ground pounded or ran over by an enemy such as a Boulder or a Chomp, it will become flat and unusable for a short period of time.

Stretch Plants appear during the final fight with Bowser at Bowser's Galaxy Reactor. They are seen in the second phase of the final battle and are used as protection against Bowser's fireballs and to be used against him.

Super Mario Galaxy 2
Stretch Plants make an appearance yet again. However, they are uncommon, only appearing in the Sky Station Galaxy, Freezy Flake Galaxy and Battle Belt Galaxy. They keep their same appearance and use from the previous game. This time, they are used to defeat certain enemies such as Prickly Piranha Plants and Silver Chomps.

Another kind of Stretch Plant appears as an enemy in the Honeybloom Galaxy during the events of the game. They are called Spiky Stretch Plants and they have red, retractable spikes. They will try to hurt Mario or Luigi by trying to hit them. However, they cannot reach very far.