# OnTrigger not firing on Alien when colliding with Marine Or Bullet

**URL:** <https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161>\
**Category:** Unity Games by Tutorials\
**Created:** [August 10, 2020, 4:47pm UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161 "2020-08-10T16:47:00Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![awicks44](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/awicks44/32/81494_2.png) [@awicks44](https://forums.kodeco.com/u/awicks44)\
**Post date:** [August 10, 2020, 4:47pm UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161/1 "2020-08-10T16:47:00Z")

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For some reason, my Alien game object instance is not being destroyed whenever I collide with the SpaceMarine, or bullet fired. I have “isTriggered” checked on the sphere collider component attached to the alien prefab. I’m not sure what’s going wrong. Been stuck for a while. Feels like the issue is something simple, but I’m lost.

![image](https://files.chunter.kodeco.com/original/3X/9/8/9848e4f1f50622f735cb23ad4fbaf834e8725769.png)

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**Author:** ![ghostwolf](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/ghostwolf/32/81494_2.png) [@ghostwolf](https://forums.kodeco.com/u/ghostwolf)\
**Post date:** [August 11, 2020, 5:32pm UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161/2 "2020-08-11T17:32:51Z")

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Could you check your layer collision matrix under physics manager

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**Author:** ![awicks44](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/awicks44/32/81494_2.png) [@awicks44](https://forums.kodeco.com/u/awicks44)\
**Post date:** [August 11, 2020, 8:56pm UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161/3 "2020-08-11T20:56:54Z")

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Thx for responding. I was actually just able to fix it. I just keep going through the step in the tutorial. I’m not actually sure what I did wrong tbh LOL. I went of the steps like 5 times. I must have had something clicked incorrectly. Kind of sucks because I was just going to skip ahead and use one of the starter projects, but those don’t show correctly in Unity (marine falling through floor, environment not colored, etc.). Anyways, I got through it in the end. Thx for the assistance.

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**Author:** ![shogunkaramazov](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/shogunkaramazov/32/108826_2.png) [@shogunkaramazov](https://forums.kodeco.com/u/shogunkaramazov)\
**Post date:** [April 7, 2021, 1:46am UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161/5 "2021-04-07T01:46:30Z")

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Opened on April 7, 2021, 1:46am UTC



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**Author:** ![shogunkaramazov](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/shogunkaramazov/32/108826_2.png) [@shogunkaramazov](https://forums.kodeco.com/u/shogunkaramazov)\
**Post date:** [April 7, 2021, 1:46am UTC](https://forums.kodeco.com/t/ontrigger-not-firing-on-alien-when-colliding-with-marine-or-bullet/117161/6 "2021-04-07T01:46:49Z")

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@awicks44 Do you still have issues with this?