Affects a large area around impact, soaking up to 20 bloons at once.
~ BTD4 description
Instead of glueing 1 bloon at a time, splatters 6 bloons at a time.
~ BTD5 description
Glue Splatter is the final upgrade for the Glue Gunner in BTD4 and the second upgrade on path 2 in BTD5. It allows the glue to splatter in the impact, glueing 6 (20 in BTD4) bloons at a time. In BTD4 it costs $2550 on Easy, $3000 on Medium and $3240 on Hard, and in BTD5 it costs $1870 on Easy, $2200 on Medium, $2375 on Hard and $2640 on Impoppable.
While this upgrade is terrific for popping and thinning out regular Bloons in the early game, it becomes nearly useless when blimps come in larger quantities, as it can't affect them. This is unless it is placed perfectly where ceramics start appearing from MOABs, as a Glue Gunner with Bloon Liquefier and Glue Splatter upgrade can take care of everything.
A good strategy is to use this tower (with this upgrade) until about Round 50. Then sell this tower and use the money to buy new towers or upgrade old ones.
In BTD4 the Glue Splatter can splat many more Bloons than in BTD5. This is probably due to being a final upgrade and the fact that it has two glue guns instead of one. Since you can get the Glue Hose in BTD5, this makes sense.