The tub-with-tail eater (or eater 5), commonly abbreviated to TWIT, is an eater composed of a block and a tub with tail.
It is capable of eating gliders from two perpendicular directions. Upon impact at the upper tip, the tub with tail becomes a melusine-like pattern, and then this trans-loaf with tailpredecessor hits the block to restore the tubmotif while triggering a grin. It is generally used to absorb gliders in situations where the standard eater is insufficient, particularly because of its edge-eating ability; an example can be found in p61 Herschel loop 2.
Variants using different still lifes are possible. For instance, the block can be replaced with a more complicated catalyst, or extra catalysts like eater bridge eater and grin reagent can be added to perturb the block. Eaters created in this way form a significant proportion of Dean Hickerson's eater collection.
If there is additional clearance requirement on the left or right, variants as a single still life with higher population are available. One is a 25-cell, 8×8 still life, which can be seen in the middle of R64 and a 21-glider synthesis for it was found by Martin Grant in July 2013. Another 27-cell vaiant found by Dave Greene on February 6, 2003 is named 7×9 eater for its bounding box with thinnest horizontal size, as shown below to the right. Both of these instances contain a boat part instead of the tub with tail, and the gliders hit it in specific ways to make an intermediate nine.